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Sample records for proximal aortic stiffness

  1. [Metabolic syndrome and aortic stiffness].

    Science.gov (United States)

    Simková, A; Bulas, J; Murín, J; Kozlíková, K; Janiga, I

    2010-09-01

    The metabolic syndrome (MS) is a cluster of risk factors that move the patient into higher level of risk category of cardiovascular disease and the probability of type 2 diabetes mellitus manifestation. Definition of MS is s based on the presence of selected risk factors as: abdominal obesity (lager waist circumpherence), atherogenic dyslipidemia (low value of HDL-cholesterol and increased level of triglycerides), increased fasting blood glucose (or type 2 DM diagnosis), higher blood pressure or antihypertensive therapy. In 2009 there were created harmonizing criteria for MS definition; the condition for assignment of MS is the presence of any 3 criteria of 5 mentioned above. The underlying disorder of MS is an insulin resistance or prediabetes. The patients with MS more frequently have subclinical (preclinical) target organ disease (TOD) which is the early sings of atherosclerosis. Increased aortic stiffness is one of the preclinical diseases and is defined by pathologically increased carotidofemoral pulse wave velocity in aorta (PWV Ao). With the aim to assess the influence of MS on aortic stiffness we examined the group of women with arterial hypertension and MS and compare them with the group of women without MS. The aortic stiffness was examined by Arteriograph--Tensiomed, the equipment working on the oscillometric principle in detection of pulsations of brachial artery. This method determines the global aortic stiffness based on the analysis of the shape of pulse curve of brachial artery. From the cohort of 49 pts 31 had MS, the subgroups did not differ in age or blood pressure level. The mean number of risk factors per person in MS was 3.7 comparing with 1.7 in those without MS. In the MS group there was more frequently abdominal obesity present (87% vs 44%), increased fasting blood glucose (81% vs 22%) and low HDL-cholesterol level. The pulse wave velocity in aorta, PWV Ao, was significantly higher in patients with MS (mean value 10,19 m/s vs 8,96 m

  2. Music decreases aortic stiffness and wave reflections.

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    Vlachopoulos, Charalambos; Aggelakas, Angelos; Ioakeimidis, Nikolaos; Xaplanteris, Panagiotis; Terentes-Printzios, Dimitrios; Abdelrasoul, Mahmoud; Lazaros, George; Tousoulis, Dimitris

    2015-05-01

    Music has been related to cardiovascular health and used as adjunct therapy in patients with cardiovascular disease. Aortic stiffness and wave reflections are predictors of cardiovascular risk. We investigated the short-term effect of classical and rock music on arterial stiffness and wave reflections. Twenty healthy individuals (22.5±2.5 years) were studied on three different occasions and listened to a 30-min music track compilation (classical, rock, or no music for the sham procedure). Both classical and rock music resulted in a decrease of carotid-femoral pulse wave velocity (PWV) immediately after the end of music listening (all pclassical or rock music in a more sustained way (nadir by 6.0% and 5.8%, respectively, at time zero post-music listening, all pmusic preference was taken into consideration, both classical and rock music had a more potent effect on PWV in classical aficionados (by 0.20 m/s, p=0.003 and 0.13 m/s, p=0.015, respectively), whereas there was no effect in rock aficionados (all p=NS). Regarding wave reflections, classical music led to a more potent response in classical aficionados (AIx decrease by 9.45%), whereas rock led to a more potent response to rock aficionados (by 10.7%, all pMusic, both classical and rock, decreases aortic stiffness and wave reflections. Effect on aortic stiffness lasts for as long as music is listened to, while classical music has a sustained effect on wave reflections. These findings may have important implications, extending the spectrum of lifestyle modifications that can ameliorate arterial function. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  3. Thoracic Endovascular Aortic Repair (TEVAR) in Proximal (Type A) Aortic Dissection: Ready for a Broader Application?

    OpenAIRE

    Nienaber, Christoph A.; Sakalihasan, Natzi; Clough, Rachel E.; Aboukoura, Mohamed; Mancuso, Enrico; Yeh, James S.M.; Defraigne, Jean-Olivier; Cheshire, Nick; Rosendahl, Ulrich Peter; Quarto, Cesare; Pepper, John

    2016-01-01

    ObjectiveThoracic endovascular aortic repair (TEVAR) has demonstrated encouraging results and is gaining increasing acceptance as a treatment option for aortic aneurysms and dissections. Yet, its role in managing proximal aortic pathologies is unknown - this is important because in proximal (Stanford type A) aortic dissections, 10-30% are not accepted for surgery, and 30-50% are technically amenable for TEVAR. We describe our case series of type A aortic dissections treated using TEVAR.Method...

  4. Weight reduction and aortic stiffness in obese children and adolescents

    DEFF Research Database (Denmark)

    Hvidt, K. N.; Olsen, M. H.; Ibsen, H.

    2015-01-01

    Little is known about the effect of weight reduction on aortic stiffness and especially so in the young. The present study investigates whether weight reduction influences aortic stiffness in obese children and adolescents. Carotid-femoral pulse wave velocity (cfPWV) and augmentation index at heart...... was found in AIx@HR75 (Delta AIx@HR75: 2.10 +/- 9.73%, P = 0.072), but changes in AIx@HR75 were related to changes in abdominal fat (Delta waist/height ratio: beta = 50.3, 95% CI 6.7-94.0, P = 0.02) and changes in total body fat percent by dual energy X-ray absorptiometry scan (Delta total body fat...... (%): beta = 0.7, 95% CI 0.1-1.3, P = 0.02) when adjusted for gender and relevant baseline confounders. In conclusion, no clear effect of weight reduction was found on aortic stiffness, although changes in AIx@HR75 were associated with changes in both abdominal fat and total body fat percent. The higher cf...

  5. A geometric reappraisal of proximal landing zones for thoracic endovascular aortic repair according to aortic arch types

    NARCIS (Netherlands)

    Marrocco-Trischitta, Massimiliano M.; de Beaufort, Hector W.; Secchi, Francesco; van Bakel, Theodorus M.; Ranucci, Marco; van Herwaarden, Joost A.; Moll, Frans L.; Trimarchi, Santi

    Objective: This study assessed whether the additional use of the aortic arch classification in type I, II, and III may complement Ishimaru's aortic arch map and provide valuable information on the geometry and suitability of proximal landing zones for thoracic endovascular aortic repair. Methods:

  6. Aging impairs smooth muscle-mediated regulation of aortic stiffness: a defect in shock absorption function?

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    Gao, Yuan Z.; Saphirstein, Robert J.; Yamin, Rina; Suki, Bela

    2014-01-01

    Increased aortic stiffness is an early and independent biomarker of cardiovascular disease. Here we tested the hypothesis that vascular smooth muscle cells (VSMCs) contribute significantly to aortic stiffness and investigated the mechanisms involved. The relative contributions of VSMCs, focal adhesions (FAs), and matrix to stiffness in mouse aorta preparations at optimal length and with confirmed VSMC viability were separated by the use of small-molecule inhibitors and activators. Using biomechanical methods designed for minimal perturbation of cellular function, we directly quantified changes with aging in aortic material stiffness. An alpha adrenoceptor agonist, in the presence of NG-nitro-l-arginine methyl ester (l-NAME) to remove interference of endothelial nitric oxide, increases stiffness by 90–200% from baseline in both young and old mice. Interestingly, increases are robustly suppressed by the Src kinase inhibitor PP2 in young but not old mice. Phosphotyrosine screening revealed, with aging, a biochemical signature of markedly impaired agonist-induced FA remodeling previously associated with Src signaling. Protein expression measurement confirmed a decrease in Src expression with aging. Thus we report here an additive model for the in vitro biomechanical components of the mouse aortic wall in which 1) VSMCs are a surprisingly large component of aortic stiffness at physiological lengths and 2) regulation of the VSMC component through FA signaling and hence plasticity is impaired with aging, diminishing the aorta's normal shock absorption function in response to stressors. PMID:25128168

  7. Determinants of aortic stiffness: 16-year follow-up of the Whitehall II study.

    Directory of Open Access Journals (Sweden)

    Nanna B Johansen

    Full Text Available Aortic stiffness is a strong predictor of cardiovascular disease endpoints. Cross-sectional studies have shown associations of various cardiovascular risk factors with aortic pulse wave velocity, a measure of aortic stiffness, but the long-term impact of these factors on aortic stiffness is unknown.In 3,769 men and women from the Whitehall II cohort, a wide range of traditional and novel cardiovascular risk factors were determined at baseline (1991-1993 and aortic pulse wave velocity was measured at follow-up (2007-2009. The prospective associations between each baseline risk factor and aortic pulse wave velocity at follow-up were assessed through sex stratified linear regression analysis adjusted for relevant confounders. Missing data on baseline determinants were imputed using the Multivariate Imputation by Chained Equations.Among men, the strongest predictors were waist circumference, waist-hip ratio, heart rate and interleukin 1 receptor antagonist, and among women, adiponectin, triglycerides, pulse pressure and waist-hip ratio. The impact of 10 centimeter increase in waist circumference on aortic pulse wave velocity was twice as large for men compared with women (men: 0.40 m/s (95%-CI: 0.24;0.56; women: 0.17 m/s (95%-CI: -0.01;0.35, whereas the opposite was true for the impact of a two-fold increase in adiponectin (men: -0.30 m/s (95%-CI: -0.51;-0.10; women: 0.61 m/s (95%-CI: -0.86;-0.35.In this large prospective study, central obesity was a strong predictor of aortic stiffness. Additionally, heart rate in men and adiponectin in women predicted aortic pulse wave velocity suggesting that strategies to prevent aortic stiffening should be focused differently by sex.

  8. Long-term results after proximal thoracic aortic redo surgery.

    Directory of Open Access Journals (Sweden)

    Martin Czerny

    Full Text Available OBJECTIVE: To evaluate early and mid-term results in patients undergoing proximal thoracic aortic redo surgery. METHODS: We analyzed 60 patients (median age 60 years, median logistic EuroSCORE 40 who underwent proximal thoracic aortic redo surgery between January 2005 and April 2012. Outcome and risk factors were analyzed. RESULTS: In hospital mortality was 13%, perioperative neurologic injury was 7%. Fifty percent of patients underwent redo surgery in an urgent or emergency setting. In 65%, partial or total arch replacement with or without conventional or frozen elephant trunk extension was performed. The preoperative logistic EuroSCORE I confirmed to be a reliable predictor of adverse outcome- (ROC 0.786, 95%CI 0.64-0.93 as did the new EuroSCORE II model: ROC 0.882 95%CI 0.78-0.98. Extensive individual logistic EuroSCORE I levels more than 67 showed an OR of 7.01, 95%CI 1.43-34.27. A EuroSCORE II larger than 28 showed an OR of 4.44 (95%CI 1.4-14.06. Multivariate logistic regression analysis identified a critical preoperative state (OR 7.96, 95%CI 1.51-38.79 but not advanced age (OR 2.46, 95%CI 0.48-12.66 as the strongest independent predictor of in-hospital mortality. Median follow-up was 23 months (1-52 months. One year and five year actuarial survival rates were 83% and 69% respectively. Freedom from reoperation during follow-up was 100%. CONCLUSIONS: Despite a substantial early attrition rate in patients presenting with a critical preoperative state, proximal thoracic aortic redo surgery provides excellent early and mid-term results. Higher EuroSCORE I and II levels and a critical preoperative state but not advanced age are independent predictors of in-hospital mortality. As a consequence, age alone should no longer be regarded as a contraindication for surgical treatment in this particular group of patients.

  9. The importance of accurate measurement of aortic stiffness in patients with chronic kidney disease and end-stage renal disease.

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    Adenwalla, Sherna F; Graham-Brown, Matthew P M; Leone, Francesca M T; Burton, James O; McCann, Gerry P

    2017-08-01

    Cardiovascular (CV) disease is the leading cause of death in chronic kidney disease (CKD) and end-stage renal disease (ESRD). A key driver in this pathology is increased aortic stiffness, which is a strong, independent predictor of CV mortality in this population. Aortic stiffening is a potentially modifiable biomarker of CV dysfunction and in risk stratification for patients with CKD and ESRD. Previous work has suggested that therapeutic modification of aortic stiffness may ameliorate CV mortality. Nevertheless, future clinical implementation relies on the ability to accurately and reliably quantify stiffness in renal disease. Pulse wave velocity (PWV) is an indirect measure of stiffness and is the accepted standard for non-invasive assessment of aortic stiffness. It has typically been measured using techniques such as applanation tonometry, which is easy to use but hindered by issues such as the inability to visualize the aorta. Advances in cardiac magnetic resonance imaging now allow direct measurement of stiffness, using aortic distensibility, in addition to PWV. These techniques allow measurement of aortic stiffness locally and are obtainable as part of a comprehensive, multiparametric CV assessment. The evidence cannot yet provide a definitive answer regarding which technique or parameter can be considered superior. This review discusses the advantages and limitations of non-invasive methods that have been used to assess aortic stiffness, the key studies that have assessed aortic stiffness in patients with renal disease and why these tools should be standardized for use in clinical trial work.

  10. Serum Neutrophil Gelatinase-Associated Lipocalin Levels and Aortic Stiffness in Noncritical Coronary Artery Disease

    Science.gov (United States)

    Soylu, Korhan; Nar, Gökay; Aksan, Gökhan; Gedikli, Ömer; İnci, Sinan; Yuksel, Serkan; Nar, Rukiye; İdil Soylu, Ayşegül; Gulel, Okan; Şahin, Mahmut

    2014-01-01

    Aim The aim of this study was to establish the degree of aortic stiffness and levels of neutrophil gelatinase-associated lipocalin (NGAL) in patients with stable ischemic heart disease. Materials and Methods Patients who were found to have stable, noncritical lesions on coronary angiography were included in the study [noncritical coronary artery disease (CAD)]. The control group consisted of those patients who had similar risk profiles and metabolic parameters without atherosclerosis on angiography. Results A total of 101 patients were included in the study of which 56 had noncritical CAD. Whereas the aortic strain (9.11 ± 3.4 vs. 14.01 ± 4.1%, p < 0.001) and aortic distensibility (3.98 ± 1.9 10−6 cm2/dyn vs. 6.33 ± 2.3 10−6 cm2/dyn, p < 0.001) were lower in the noncritical CAD group, the aortic stiffness index was higher (6.34 ± 3.9 vs. 3.37 ± 2.4, p < 0.001) as compared to controls. Serum NGAL levels were higher in the noncritical CAD group (79.29 ± 38.8 vs. 48.05 ± 21.4 ng/ml, p < 0.001). NGAL levels were negatively correlated with aortic strain (p < 0.01, r = 0.57) and distensibility (p < 0.001, r = 0.62), but positively correlated with the aortic stiffness index (p < 0.001, r = 0.72). Conclusion We show that in patients with noncritical CAD, the degree of aortic stiffness and NGAL levels are higher. These markers can be used as tools for further risk stratification of patients with noncritical CAD. PMID:25737678

  11. Metabolic syndrome and its effect on aortic stiffness in premenopausal women.

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    Simkova, A; Bulas, J; Balogova, S; Reptova, A; Kisa, B; Luha, J; Kinova, S

    2013-01-01

    Metabolic syndrome (MS) is a cluster of proatherogenic risk factors (RF) (abdominal obesity, atherogenic dyslipidemia, impaired fasting glucose or type 2 diabetes mellitus, higher blood pressure or antihypertensive therapy) that move patients into a higher risk for development of cardiovascular disease (CVD) and type 2 diabetes. The preclinical (subclinical) target organ diseases (SOD) are early signs of atherosclerosis. An increased aortic stiffness characterised by an increased pulse wave velocity in aorta (PWV Ao) is one of SOD.The aim of the present study was to assess the impact of metabolic syndrome (MS) on aortic wall stiffness and the risk profile in premenopausal women. The aortic stiffness was measured using Arteriograph-Tensiomed, based on oscillometric measurement and analysis of the shape of brachial pulse wave, giving the PWV Ao. The results of measurements characterise a global aortic stiffness. We examined 81 premenopausal women (without history of CVD). The MS (according to the 2009 "harmonizing" definition) was present in 31 women (mean age 41.5 y), in the control group, there were 50 women (39 y). The most frequent components of MS were abdominal obesity (93 % vs 42%), arterial hypertension (68 % vs 10 %) and dyslipidemia (29 % vs 8 %). The PWV Ao was significantly higher in women with MS (9.26 m/s) compared to the control group (7.44 m/s). The aortic stiffness in women with MS compared to controls was significantly higher despite a presumed general protective hormonal effect on cardiovascular system in women with child-bearing potential (Tab. 4, Ref. 25).

  12. Comparison of arterial stiffness and microcirculatory changes following abdominal aortic aneurysm grafting.

    LENUS (Irish Health Repository)

    Moloney, M A

    2012-02-01

    BACKGOUND: Abdominal aortic aneurysm (AAA) surgery provides a unique opportunity to study the impact of arterial stiffness on central haemodynamics, reflected in augmentation index (AI). The aneurysmal aorta is significantly stiffer than undilated age-matched aorta. AIM: We investigated whether replacement of an aneurysmal aorta with a compliant graft would result in a decrease in AI, which would thus decrease myocardial workload parameters. METHODS: Patients undergoing elective open or endovascular AAA repair were assessed with applanation tonometry and laser fluximetry pre-operatively, immediately and long-term post-operatively. RESULTS: Replacement of a small segment of abnormal conduit vessel resulted in improvements in AI, demonstrating that arterial stiffness can be surgically manipulated. CONCLUSIONS: These results reflect a decreased myocardial workload post-aortic grafting. This decrease in AI is important from a risk factor management perspective, and arterial stiffness should become a further recognised and screened for risk factor in patients with known aneurysmal disease.

  13. Comparison of arterial stiffness and microcirculatory changes following abdominal aortic aneurysm grafting.

    LENUS (Irish Health Repository)

    Moloney, M A

    2010-11-11

    BACKGOUND: Abdominal aortic aneurysm (AAA) surgery provides a unique opportunity to study the impact of arterial stiffness on central haemodynamics, reflected in augmentation index (AI). The aneurysmal aorta is significantly stiffer than undilated age-matched aorta. AIM: We investigated whether replacement of an aneurysmal aorta with a compliant graft would result in a decrease in AI, which would thus decrease myocardial workload parameters. METHODS: Patients undergoing elective open or endovascular AAA repair were assessed with applanation tonometry and laser fluximetry pre-operatively, immediately and long-term post-operatively. RESULTS: Replacement of a small segment of abnormal conduit vessel resulted in improvements in AI, demonstrating that arterial stiffness can be surgically manipulated. CONCLUSIONS: These results reflect a decreased myocardial workload post-aortic grafting. This decrease in AI is important from a risk factor management perspective, and arterial stiffness should become a further recognised and screened for risk factor in patients with known aneurysmal disease.

  14. Segmental Aortic Stiffness in Children and Young Adults With Connective Tissue Disorders: Relationships With Age, Aortic Size, Rate of Dilation, and Surgical Root Replacement.

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    Prakash, Ashwin; Adlakha, Himanshu; Rabideau, Nicole; Hass, Cara J; Morris, Shaine A; Geva, Tal; Gauvreau, Kimberlee; Singh, Michael N; Lacro, Ronald V

    2015-08-18

    Aortic diameter is an imperfect predictor of aortic complications in connective tissue disorders (CTDs). Novel indicators of vascular phenotype severity such as aortic stiffness and vertebral tortuosity index have been proposed. We assessed the relation between aortic stiffness by cardiac MRI, surgical root replacement, and rates of aortic root dilation in children and young adults with CTDs. Retrospective analysis of cardiac MRI data on children and young adults with a CTD was performed to derive aortic stiffness measures (strain, distensibility, and β-stiffness index) at the aortic root, ascending aorta, and descending aorta. Vertebral tortuosity index was calculated as previously described. Rate of aortic root dilation before cardiac MRI was calculated as change in echocardiographic aortic root diameter z score per year. In 83 CTD patients (median age, 24 years; range, 1-55; 17% age; 60% male), ascending aorta distensibility was reduced in comparison with published normative values: median z score, -1.93 (range, -8.7 to 1.3; Pyoung adults with CTDs. © 2015 American Heart Association, Inc.

  15. Aortic stiffness and diameter predict progressive aortic dilatation in patients with Marfan syndrome

    NARCIS (Netherlands)

    Nollen, Gijs J.; Groenink, Maarten; Tijssen, Jan G. P.; van der Wall, Ernst E.; Mulder, Barbara J. M.

    2004-01-01

    Aim Patients with Marfan syndrome may develop dissection due to progressive dilatation in the entire aorta, which is not always predictable by mere anatomic assessment of the aortic diameter, especially of the descending aorta. The aim of this study was to identify the predictive value of aortic

  16. Aortic stiffness is associated with white matter integrity in patients with type 1 diabetes

    International Nuclear Information System (INIS)

    Tjeerdema, Nathanja; Schinkel, Linda D. van; Westenberg, Jos J.; Elderen, Saskia G. van; Buchem, Mark A. van; Grond, Jeroen van der; Roos, Albert de; Smit, Johannes W.

    2014-01-01

    To assess the association between aortic pulse wave velocity (PWV) as a marker of arterial stiffness and diffusion tensor imaging of brain white matter integrity in patients with type 1 diabetes using advanced magnetic resonance imaging (MRI) technology. Forty-one patients with type 1 diabetes (23 men, mean age 44 ± 12 years, mean diabetes duration 24 ± 13 years) were included. Aortic PWV was assessed using through-plane velocity-encoded MRI. Brain diffusion tensor imaging (DTI) measurements were performed on 3-T MRI. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were calculated for white and grey matter integrity. Pearson correlation and multivariable linear regression analyses including cardiovascular risk factors as covariates were assessed. Multivariable linear regression analyses revealed that aortic PWV is independently associated with white matter integrity FA (β = -0.777, p = 0.008) in patients with type 1 diabetes. This effect was independent of age, gender, mean arterial pressure, body mass index, smoking, duration of diabetes and glycated haemoglobin levels. Aortic PWV was not significantly related to grey matter integrity. Our data suggest that aortic stiffness is independently associated with reduced white matter integrity in patients with type 1 diabetes. (orig.)

  17. Aortic stiffness is associated with white matter integrity in patients with type 1 diabetes

    Energy Technology Data Exchange (ETDEWEB)

    Tjeerdema, Nathanja; Schinkel, Linda D. van [Leiden University Medical Center, Department of Endocrinology and General Internal Medicine (C7-Q), Albinusdreef 2, PO Box 9600, Leiden (Netherlands); Westenberg, Jos J.; Elderen, Saskia G. van; Buchem, Mark A. van; Grond, Jeroen van der; Roos, Albert de [Leiden University Medical Center, Department of Radiology, Leiden (Netherlands); Smit, Johannes W. [Leiden University Medical Center, Department of Endocrinology and General Internal Medicine (C7-Q), Albinusdreef 2, PO Box 9600, Leiden (Netherlands); University Medical Center Nijmegen, Department of General Internal Medicine, Nijmegen (Netherlands)

    2014-09-15

    To assess the association between aortic pulse wave velocity (PWV) as a marker of arterial stiffness and diffusion tensor imaging of brain white matter integrity in patients with type 1 diabetes using advanced magnetic resonance imaging (MRI) technology. Forty-one patients with type 1 diabetes (23 men, mean age 44 ± 12 years, mean diabetes duration 24 ± 13 years) were included. Aortic PWV was assessed using through-plane velocity-encoded MRI. Brain diffusion tensor imaging (DTI) measurements were performed on 3-T MRI. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were calculated for white and grey matter integrity. Pearson correlation and multivariable linear regression analyses including cardiovascular risk factors as covariates were assessed. Multivariable linear regression analyses revealed that aortic PWV is independently associated with white matter integrity FA (β = -0.777, p = 0.008) in patients with type 1 diabetes. This effect was independent of age, gender, mean arterial pressure, body mass index, smoking, duration of diabetes and glycated haemoglobin levels. Aortic PWV was not significantly related to grey matter integrity. Our data suggest that aortic stiffness is independently associated with reduced white matter integrity in patients with type 1 diabetes. (orig.)

  18. Aortic-Brachial Pulse Wave Velocity Ratio: A Measure of Arterial Stiffness Gradient Not Affected by Mean Arterial Pressure.

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    Fortier, Catherine; Desjardins, Marie-Pier; Agharazii, Mohsen

    2018-03-01

    Aortic stiffness, measured by carotid-femoral pulse wave velocity (cf-PWV), is used for the prediction of cardiovascular risk. This mini-review describes the nonlinear relationship between cf-PWV and operational blood pressure, presents the proposed methods to adjust for this relationship, and discusses a potential place for aortic-brachial PWV ratio (a measure of arterial stiffness gradient) as a blood pressure-independent measure of vascular aging. PWV is inherently dependent on the operational blood pressure. In cross-sectional studies, PWV adjustment for mean arterial pressure (MAP) is preferred, but still remains a nonoptimal approach, as the relationship between PWV and blood pressure is nonlinear and varies considerably among individuals due to heterogeneity in genetic background, vascular tone, and vascular remodeling. Extrapolations from the blood pressure-independent stiffness parameter β (β 0 ) have led to the creation of stiffness index β, which can be used for local stiffness. A similar approach has been used for cardio-ankle PWV to generate a blood pressure-independent cardio-ankle vascular index (CAVI). It was recently demonstrated that stiffness index β and CAVI remain slightly blood pressure-dependent, and a more appropriate formula has been proposed to make the proper adjustments. On the other hand, the negative impact of aortic stiffness on clinical outcomes is thought to be mediated through attenuation or reversal of the arterial stiffness gradient, which can also be influenced by a reduction in peripheral medium-sized muscular arteries in conditions that predispose to accelerate vascular aging. Arterial stiffness gradient, assessed by aortic-brachial PWV ratio, is emerging to be at least as good as cf-PWV for risk prediction, but has the advantage of not being affected by operating MAP. The negative impacts of aortic stiffness on clinical outcomes are proposed to be mediated through attenuation or reversal of arterial stiffness gradient

  19. Computed tomography-based anatomic characterization of proximal aortic dissection with consideration for endovascular candidacy.

    Science.gov (United States)

    Moon, Michael C; Greenberg, Roy K; Morales, Jose P; Martin, Zenia; Lu, Qingsheng; Dowdall, Joseph F; Hernandez, Adrian V

    2011-04-01

    Proximal aortic dissections are life-threatening conditions that require immediate surgical intervention to avert an untreated mortality rate that approaches 50% at 48 hours. Advances in computed tomography (CT) imaging techniques have permitted increased characterization of aortic dissection that are necessary to assess the design and applicability of new treatment paradigms. All patients presenting during a 2-year period with acute proximal aortic dissections who underwent CT scanning were reviewed in an effort to establish a detailed assessment of their aortic anatomy. Imaging studies were assessed in an effort to document the location of the primary proximal fenestration, the proximal and distal extent of the dissection, and numerous morphologic measurements pertaining to the aortic valve, root, and ascending aorta to determine the potential for an endovascular exclusion of the ascending aorta. During the study period, 162 patients presented with proximal aortic dissections. Digital high-resolution preoperative CT imaging was performed on 76 patients, and 59 scans (77%) were of adequate quality to allow assessment of anatomic suitability for treatment with an endograft. In all cases, the dissection plane was detectable, yet the primary intimal fenestration was identified in only 41% of the studies. Scans showed 24 patients (32%) appeared to be anatomically amenable to such a repair (absence of valvular involvement, appropriate length and diameter of proximal sealing regions, lack of need to occlude coronary vasculature). Of the 42 scans that were determined not to be favorable for endovascular repair, the most common exclusion finding was the absence of a proximal landing zone (n = 15; 36%). Appropriately protocoled CT imaging provides detailed anatomic information about the aortic root and ascending aorta, allowing the assessment of which dissections have proximal fenestrations that may be amenable to an endovascular repair. Copyright © 2011 Society for

  20. Dietary Sodium Restriction and Association with Urinary Marinobufagenin, Blood Pressure, and Aortic Stiffness

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    Fedorova, Olga V.; Racine, Matthew L.; Geolfos, Candace J.; Gates, Phillip E.; Chonchol, Michel; Fleenor, Bradley S.; Lakatta, Edward G.; Bagrov, Alexei Y.; Seals, Douglas R.

    2013-01-01

    Summary Background and objectives Systolic BP and large elastic artery stiffness both increase with age and are reduced by dietary sodium restriction. Production of the natriuretic hormone marinobufagenin, an endogenous α1 Na+,K+-ATPase inhibitor, is increased in salt-sensitive hypertension and contributes to the rise in systolic BP during sodium loading. Design, setting, participants, & measurements The hypothesis was that dietary sodium restriction performed in middle-aged/older adults (eight men and three women; 60±2 years) with moderately elevated systolic BP (139±2/83±2 mmHg) would reduce urinary marinobufagenin excretion as well as systolic BP and aortic pulse-wave velocity (randomized, placebo-controlled, and crossover design). This study also explored the associations among marinobufagenin excretion with systolic BP and aortic pulse-wave velocity across conditions of 5 weeks of a low-sodium (77±9 mmol/d) and 5 weeks of a normal-sodium (144±7 mmol/d) diet. Results Urinary marinobufagenin excretion (weekly measurements; 25.4±1.8 versus 30.7±2.1 pmol/kg per day), systolic BP (127±3 versus 138±5 mmHg), and aortic pulse-wave velocity (700±40 versus 843±36 cm/s) were lower during the low- versus normal-sodium condition (all Psodium excretion (slope=0.46, Psodium condition (both Psodium restriction reduces urinary marinobufagenin excretion and that urinary marinobufagenin excretion is positively associated with systolic BP, aortic stiffness (aortic pulse-wave velocity), and endothelial cell expression of the oxidant enzyme NAD(P)H oxidase. Importantly, marinobufagenin excretion is positively related to systolic BP over ranges of sodium intake typical of an American diet, extending previous observations in rodents and humans fed experimentally high-sodium diets. PMID:23929930

  1. Aortic dilatation in Marfan syndrome: role of arterial stiffness and fibrillin-1 variants.

    Science.gov (United States)

    Salvi, Paolo; Grillo, Andrea; Marelli, Susan; Gao, Lan; Salvi, Lucia; Viecca, Maurizio; Di Blasio, Anna Maria; Carretta, Renzo; Pini, Alessandro; Parati, Gianfranco

    2018-01-01

    Marfan syndrome (MFS) is an autosomal dominant genetic disorder characterized by aortic root dilation and dissection and an abnormal fibrillin-1 synthesis. In this observational study, we evaluated aortic stiffness in MFS and its association with ascending aorta diameters and fibrillin-1 genotype. A total of 116 Marfan adult patients without history of cardiovascular surgery, and 144 age, sex, blood pressure and heart rate matched controls were enrolled. All patients underwent arterial stiffness evaluation through carotid-femoral pulse wave velocity (PWV) and central blood pressure waveform analysis (PulsePen tonometer). Fibrillin-1 mutations were classified based on the effect on the protein, into 'dominant negative' and 'haploinsufficient' mutations. PWV and central pulse pressure were significantly higher in MFS patients than in controls [respectively 7.31 (6.81-7.44) vs. 6.69 (6.52-6.86) m/s, P = 0.0008; 41.3 (39.1-43.5) vs. 34.0 (32.7-35.3) mmHg, P < 0.0001], with a higher age-related increase of PWV in MFS (β 0.062 vs. 0.036). Pressure amplification was significantly reduced in MFS [18.2 (15.9-20.5) vs. 33.4 (31.6-35.2)%, P < 0.0001]. Central pressure profile was altered even in MFS patients without aortic dilatation. Multiple linear regression models showed that PWV independently predicted aortic diameters at the sinuses of Valsalva (ß = 0.243, P = 0.002) and at the sinotubular junction (ß = 0.186, P = 0.048). PWV was higher in 'dominant negative' than 'haploinsufficient' fibrillin-1 mutations [7.37 (7.04-7.70) vs. 6.60 (5.97-7.23) m/s, P = 0.035], although this difference was not significant after adjustment. Aortic stiffness is increased in MFS, independently from fibrillin-1 genotype and is associated with diameters of ascending aorta. Alterations in central hemodynamics are present even when aortic diameter is within normal limits. Our findings suggest an accelerated arterial aging in MFS.

  2. Elastic properties of the aorta and factors affecting aortic stiffness in patients with

    Directory of Open Access Journals (Sweden)

    Derya Tok

    2012-09-01

    Full Text Available Objectives: In this study, we evaluated aortic stiffnessand echocardiographic and laboratory factors affectingaortic stiffness in patients with metabolic syndrome(MetS.Materials and methods: Forty-six patients (25 male,mean age 47.3±6.5 years with the diagnosis of MetS accordingto the Adult Treatment Panel III Final Report criteriawere included. Forty-four age and gender matchedhealthy subjects (18 male, mean age 46.0±6.1 yearswere recruited as the control group. Aortic strain, distensibilityand stiffness index were calculated by M-modeechocardiography and diastolic parameters were measured.Results: Left ventricular mass index (LVMI, decelerationtime (DT, isovolumic relaxation time (IVRT wereincreased and mitral E/A ratio was decreased in patientswith MetS compared to controls. In the MetS patients,aortic distensibility was significantly decreased (10.4±3.5cm2.dyn-1.10-6 vs. 12.7±3.4 cm2.dyn-1.10-6, p=0.002,and ASI was significantly increased (6.5±2.0 vs. 3.2±0.8,p<0.001. ASI was positively correlated with triglycerides,fasting glucose, uric acid, hsCRP, LVMI, DT, IVRT andsystolic blood pressure level, and was negatively correlatedwith HDL-cholesterol and mitral E/A ratio. In regressionanalysis, hsCRP (p=0.05 and systolic blood pressurelevel (p<0.001 were independent predictors of ASI.Conclusions: ASI is increased in patients with MetS. Inthese patients; decrease in aortic elasticity properties wasassociated with left ventricular diastolic dysfunction. Highsystolic pressure and hsCRP levels were found to be independentpredictors of ASI.Key words: Metabolic syndrome, Echocardiography,elastic properties of aorta, hsCRP

  3. P-wave dispersion and its relationship to aortic stiffness in patients with acute myocardial infarction after cardiac rehabilitation

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    Rezzan Deniz Acar

    2014-07-01

    Full Text Available BACKGROUND: The aim of our study was to investigate the P-wave dispersion from standard electrocardiograms (ECGs in patients with acute myocardial infarction (AMI after cardiac rehabilitation (CR and determine its relation to arterial stiffness. METHODS: This is a prospective study included 33 patients with AMI and successfully re-vascularized by percutaneous coronary intervention (PCI underwent CR. Left ventricular ejection fraction (LVEF was measured by biplane Simpson’s method. Left atrium (LA volume was calculated. The maximum and minimum durations of P-waves (Pmax and Pmin, respectively were detected, and the difference between Pmax and Pmin was defined as P-wave dispersion (Pd = Pmax–Pmin. Aortic elasticity parameters were measured. RESULTS: LVEF was better after CR. The systolic and diastolic blood pressures decreased after CR, these differences were statistically significant. With exercise training, LA volume decreased significantly. Pmax and Pd values were significantly shorter after the CR program. The maximum and minimum P-waves and P-wave dispersion after CR were 97 ± 6 ms, 53 ± 5 ms, and 44 ± 5 ms, respectively. Aortic strain and distensibility increased and aortic stiffness index was decreased significantly. Aortic stiffness index was 0.4 ± 0.2 versus 0.3 ± 0.2, P = 0.001. Aortic stiffness and left atrial volume showed a moderate positive correlation with P-wave dispersion (r = 0.52, P = 0.005; r = 0.64, P = 0.000, respectively. CONCLUSION: This study showed decreased arterial stiffness indexes in AMI patient’s participated CR, with a significant relationship between the electromechanical properties of the LA that may raise a question of the preventive effect of CR from atrial fibrillation and stroke in patients with acute myocardial infarction.   Keywords: Cardiac Rehabilitation, P-Wave Dispersion, Aortic Stiffness, Acute Myocardial Infarction 

  4. Angular (Gothic) aortic arch leads to enhanced systolic wave reflection, central aortic stiffness, and increased left ventricular mass late after aortic coarctation repair: evaluation with magnetic resonance flow mapping.

    Science.gov (United States)

    Ou, Phalla; Celermajer, David S; Raisky, Olivier; Jolivet, Odile; Buyens, Fanny; Herment, Alain; Sidi, Daniel; Bonnet, Damien; Mousseaux, Elie

    2008-01-01

    We sought to investigate the mechanism whereby a particular deformity of the aortic arch, an angulated Gothic shape, might lead to hypertension late after anatomically successful repair of aortic coarctation. Fifty-five normotensive patients with anatomically successful repair of aortic coarctation and either a Gothic (angulated) or a Romanesque (smooth and rounded) arch were studied with magnetic resonance angiography and flow mapping in both the ascending and descending aortas. Systolic waveforms, central aortic stiffness, and pulse velocity were measured. We hypothesized that arch angulation would result in enhanced systolic wave reflection with loss of energy across the aortic arch, as well as increased central aortic stiffness. Twenty patients were found to have a Gothic, and 35 a Romanesque, arch. Patients with a Gothic arch showed markedly augmented systolic wave reflection (12 +/- 6 vs 5 +/- 0.3 mL, P Gothic arch (5.6 +/- 1.1 vs 4.1 +/- 1 m/s, P Gothic aortic arch is associated with increased systolic wave reflection, as well as increased central aortic stiffness and left ventricular mass index. These findings explain (at least in part) the association between this pattern of arch geometry and late hypertension at rest and on exercise in subjects after coarctation repair.

  5. Relation of the aortic stiffness with the GRACE risk score in patients with the non ST-segment elevation myocardial infarction.

    Science.gov (United States)

    Omer, Gedikli; Gokhan, Aksan; Adem, Uzun; Sabri, Demircan; Korhan, Soylu

    2014-01-01

    Current guidelines recommend clinical risk scoring systems for the patients diagnosed and determinated treatment strategy with in Non-ST-elevation elevation myocardial infarction (NSTEMI). Previous studies demonstrated association between aortic elasticity properties, stiffness and severity CAD. However, the associations between Aortic stiffness, elasticity properties and clinical risk scores have not been investigated. In the present study we have evaluated the relation between the Global Registry of Acute Coronary Events (GRACE) risk score and aortic stiffness in patients with NSTEMI. We prospectively analyzed 87 consecutive patients with NSTEMI. Aortic elastic parameter and stiffness parameter were calculated from the echocardiographically derived thoracic aortic diameters (mm/m(2)), and the measurement of pulse pressure obtained by cuff sphygmomanometry. We have categorized the patients in to two groups as low ((n = 45) (GRACE risk score ≤ 140)) and high ((n = 42) (GRACE risk score > 140)) risk group according to GRACE risk score and compare the both groups. Table 1 shows baseline characteristics of patients. Our study showed that Aortic strain was significantly low (3.5 ± 1.4, 7.9 ± 2.3 respectively, p < 0.001) and aortic stiffness index was significantly high (3.9 ± 0.38; 3 ± 0.35, respectively, p < 0.001) in the high risk group values compared to those with low risk group. The aortic stiffness index was the only independent predictor of GRACE risk score (OR: 119.390; 95% CI: 2.925-4872.8; p = 0.011) in multivariate analysis. We found a significant correlation between aortic stiffness, impaired elasticity and GRACE risk score. Aortic stiffness index was the only independent variable of the high GRACE risk score. The inclusion of aortic stiffness into the GRACE risk score could allow improved risk classification of patients with ACS at admission and this may be important in the diagnosis, follow up and treatment of the patients.

  6. Relation of Bicuspid Aortic Valve Morphology to the Dilatation Pattern of the Proximal Aorta: Focus on the Transvalvular Flow

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    Evaldas Girdauskas

    2012-01-01

    Full Text Available Whether the dilatation of proximal aorta in patients with bicuspid aortic valve is secondary to hemodynamic effects related to the abnormal aortic valve or a primary manifestation of the genetic disorder remains controversial. We discuss in this paper the recent data on the BAV function and transvalvular flow patterns in relation with the dilatation type of the proximal aorta. Different morphological forms of bicuspid aortic valve in relation with the specific transvalvular blood flow patterns are focus of the first paragraph of this paper. In the second part of this paper we present the pathogenetic insight into the different clinically observed phenotypes of bicuspid aortic valve disease (i.e., association of proximal aortic shapes with the specific cusp fusion patterns, based on the data from recent rheological studies.

  7. Estimated Aortic Stiffness is Independently Associated with Cardiac Baroreflex Sensitivity in Humans: Role of Aging and Habitual Endurance Exercise

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    Pierce, Gary L.; Harris, Stephen A.; Seals, Douglas R.; Casey, Darren P.; Barlow, Patrick B.; Stauss, Harald M.

    2016-01-01

    We hypothesized that differences in cardiac baroreflex sensitivity (BRS) would be independently associated with aortic stiffness and augmentation index (AI), clinical biomarkers of cardiovascular disease (CVD) risk, among young sedentary and middle-aged/older sedentary and endurance-trained adults. A total of 36 healthy middle-aged/older (age 55-76 years, n=22 sedentary; n=14 endurance-trained) and 5 young sedentary (age 18-31 years) adults were included in a cross-sectional study. A subset of the middle-aged/older sedentary adults (n=12) completed an 8-week aerobic exercise intervention. Invasive brachial artery blood pressure waveforms were used to compute spontaneous cardiac BRS (via sequence technique) and estimated aortic pulse wave velocity (PWV) and AI (AI, via brachial-aortic transfer function and wave separation analysis). In the cross-sectional study, cardiac BRS was 71% lower in older compared with young sedentary adults (Pendurance exercise (P=0.03). In a regression model that included age, sex, resting heart rate, mean arterial pressure (MAP), body mass index and maximal exercise oxygen uptake, estimated aortic PWV (β±SE = −5.76 ± 2.01, P=0.01) was the strongest predictor of BRS (Model R2=0.59, Pendurance exercise-related differences in cardiac BRS are independently associated with corresponding alterations in aortic PWV among healthy adults, consistent with a mechanistic link between variations in the sensitivity of the baroreflex and aortic stiffness with age and exercise. PMID:26911535

  8. Estimated aortic stiffness is independently associated with cardiac baroreflex sensitivity in humans: role of ageing and habitual endurance exercise.

    Science.gov (United States)

    Pierce, G L; Harris, S A; Seals, D R; Casey, D P; Barlow, P B; Stauss, H M

    2016-09-01

    We hypothesised that differences in cardiac baroreflex sensitivity (BRS) would be independently associated with aortic stiffness and augmentation index (AI), clinical biomarkers of cardiovascular disease risk, among young sedentary and middle-aged/older sedentary and endurance-trained adults. A total of 36 healthy middle-aged/older (age 55-76 years, n=22 sedentary and n=14 endurance-trained) and 5 young sedentary (age 18-31 years) adults were included in a cross-sectional study. A subset of the middle-aged/older sedentary adults (n=12) completed an 8-week-aerobic exercise intervention. Invasive brachial artery blood pressure waveforms were used to compute spontaneous cardiac BRS (via sequence technique), estimated aortic pulse wave velocity (PWV) and AI (AI, via brachial-aortic transfer function and wave separation analysis). In the cross-sectional study, cardiac BRS was 71% lower in older compared with young sedentary adults (Pendurance exercise (P=0.03). In a regression model that included age, sex, resting heart rate, mean arterial pressure (MAP), body mass index and maximal exercise oxygen uptake, estimated aortic PWV (β±s.e.=-5.76±2.01, P=0.01) was the strongest predictor of BRS (model R(2)=0.59, Pendurance-exercise-related differences in cardiac BRS are independently associated with corresponding alterations in aortic PWV among healthy adults, consistent with a mechanistic link between variations in the sensitivity of the baroreflex and aortic stiffness with age and exercise.

  9. Directional tip control technique for optimal stent graft alignment in angulated proximal aortic landing zones

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    Toshio Takayama, MD, PhD

    2017-06-01

    Full Text Available Angulated anatomy in the aorta, such as tortuous infrarenal aortic necks or steep aortic arches, is a significant challenge for endovascular aortic repair because it often causes inadequate sealing and fixation, which may lead to treatment failure. We have developed a technique using off-the-shelf equipment to precisely control the deployment of stent grafts in challenging landing zones. The key of this technique is to create a through-and-through wire between two access sites and to use a guiding device over the wire. This technique is best used with stent grafts without nose cones. We present an endovascular aneurysm repair case and a thoracic endovascular aortic repair case with challenging proximal landing zones treated by this technique. In both cases, technical success was attained, and follow-up imaging demonstrated well-aligned stent grafts. Our directional tip control technique is easy and effective. It can be a good technical solution for endovascular aortic treatment in angulated anatomy.

  10. Doppler Echocardiography Assessment of Aortic Stiffness in Female Adolescents with Anorexia Nervosa.

    Science.gov (United States)

    Escudero, Carolina A; Potts, James E; Lam, Pei-Yoong; De Souza, Astrid M; Mugford, Gerald J; Sandor, George G S

    2018-03-17

    Anorexia nervosa (AN) is associated with abnormalities in biomarkers of cardiovascular risk. Arterial stiffness, as measured by pulse-wave velocity (PWV), is also a risk factor for cardiovascular disease. The aims of this study were to determine the stiffness of the aorta in female adolescents with AN and to determine if either the severity or the type of AN was associated with PWV. This was a retrospective case-control study. Adolescent patients with a clinical diagnosis of AN were included. Aortic diameter and pulse-wave transit time over a portion of the thoracic aorta were measured using Doppler echocardiography, and PWV was calculated. There were 94 female patients with AN and 60 adolescent female control subjects. There was no significant difference in age between patients with AN and control subjects (15.5 ± 1.7 vs 15.1 ± 2.6 years, P = .220). Body mass index (16.0 ± 2.4 vs 19.7 ± 2.7 kg/m 2 , P study suggests that patients with AN may be at increased risk for future cardiovascular disease. Future studies are required to determine the reversibility of these changes with weight restoration. Copyright © 2018 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

  11. Epicardial fat volume and aortic stiffness in healthy individuals. A quantitative cardiac magnetic resonance study

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    Homsi, R.; Thomas, D.; Meier-Schroers, M.; Dabir, D.; Kuetting, D.; Luetkens, J.A.; Marx, C.; Schild, H.H. [Bonn University Hospital (Germany). Radiology; Gieseke, J. [Philips Healthcare, Hamburg (Germany); Sprinkart, A. [Bonn University Hospital (Germany). Radiology; Bochum Univ. (Germany). Inst. of Medical Engineering

    2016-09-15

    To determine epicardial fat volume (EFV) and aortic stiffness (assessed by aortic pulse wave velocity (PWV)) in healthy individuals, and to investigate the relationship of these parameters, and their association with body mass index (BMI) and age. 58 subjects (29 men, mean age 44.7 ± 13.9 years[y]) underwent a CMR exam at 1.5 Tesla. A 2 D velocity-encoded CMR scan was acquired to determine PWV. The EFV was measured based on a 3 D-mDixon sequence. Group comparisons were made between younger (age < 45y; n=30; mean age 33.4 ± 6.6y) and older (> 45y; n=28; 56.7 ± 8.4y) subjects and between subjects with a BMI < 25 kg/m{sup 2} (n=28; BMI 21.9 ± 2.5 kg/m{sup 2}) and a BMI > 25 kg/m{sup 2} (n=30; 28.7 ± 4.0 kg/m{sup 2}). Associations between the determined parameters were assessed by analyses of covariance (ANCOVAs). The mean values of PWV and EFV (normalized to body surface area) were 6.9 ±1.9 m/s and 44.2 ± 25.0 ml/m{sup 2}, respectively. The PWV and EFV were significantly higher in the older group (PWV=7.9 ± 2.0 m/s vs. 6.0 ± 1.2 m/s; EFV=54.7 ml/m{sup 2} vs. 34.5 ml/m{sup 2}; p < 0.01, each), with no significant differences in BMI or sex. In the overweighted group the EFV was significantly higher than in subjects with a BMI < 25kg/m{sup 2} (EFV=56.1 ± 27.1 ml/m{sup 2} vs. 31.5 ± 14.6 ml/m{sup 2}; p < 0.01) but without a significant difference in PWV. ANCOVA revealed a significant correlation between EFV and PWV, also after adjustment for age (p=0.025). An association was found between age and EFV as well as PWV. EFV and PWV were related to each other also after adjustment for age. The metabolic and pro-inflammatory activity found with increased epicardial fat volume may promote the development of atherosclerosis and aortic stiffness. CMR may be valuable for future studies investigating the relationship between EFV and PWV in patients with increased cardiovascular risk.

  12. Effects of 6 months of abatacept treatment on aortic stiffness in patients with rheumatoid arthritis

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    Mathieu S

    2013-12-01

    Full Text Available Sylvain Mathieu,1,2 Marion Couderc,1,2 Baptiste Glace,1,2 Bruno Pereira,2,3 Anne Tournadre,1,2 Jean-Jacques Dubost,1,2 Martin Soubrier1,21Department of Rheumatology, Gabriel-Montpied Hospital, 2Faculty of Medicine, University Clermont 1, 3Délégation de la Recherche Clinique, Gabriel-Montpied Hospital, Clermont-Ferrand, FranceBackground: Systemic inflammation plays an important role in the increased cardiac risk observed in rheumatoid arthritis (RA. Effective control of inflammation and disease activity may be of benefit in reducing cardiovascular risk in RA patients.Objective: Our study was conducted in patients with active RA to investigate the effects of 24-week abatacept treatment on aortic stiffness measured by pulse wave velocity (PWV.Results: The study included 21 patients, of whom 17 were females, with a mean age of 65.2±13.7 years. Ten patients had positive rheumatoid factors, 16 positive anti-citrullinated protein antibodies, and 19 presented an erosive form of RA. Sixteen patients were nonresponders to anti-tumor necrosis factor-alpha treatments. After 6 months of abatacept treatment, there was a significant increase in PWV levels (9.8±2.9 versus 8.5±3.9 m/second; P=0.02. A nonsignificant increase in total cholesterol and low-density lipoprotein cholesterol was observed. There was also a significant increase in high-density lipoprotein cholesterol levels, which led to a nonsignificant decrease in atherogenic index. The improvement in disease activity was significant, and there was a decrease of systemic inflammatory parameters, but without reaching statistical significancy. Changes in PWV were significantly correlated with changes in Disease Activity Score on 28 joints based on erythrocyte sedimentation rate (r=0.46; P=0.035 and in high-density lipoprotein cholesterol (r=-0.38; P=0.046. No correlation was observed with changes in C-reactive protein and in other parameters of lipid profile or in steroid dose.Conclusion: The

  13. Aortic stiffness is associated with visceral adiposity in older adults enrolled in the study of health, aging, and body composition.

    Science.gov (United States)

    Sutton-Tyrrell, K; Newman, A; Simonsick, E M; Havlik, R; Pahor, M; Lakatta, E; Spurgeon, H; Vaitkevicius, P

    2001-09-01

    The central arteries stiffen with age, causing hemodynamic alterations that have been associated with cardiovascular events. Changes in body fat with age may be related to aortic stiffening. The association between vascular stiffness and body fat was evaluated in 2488 older adults (mean age, 74 years; 52% female; 40% black) enrolled in the Study of Health, Aging, and Body Composition (Health ABC), a prospective study of changes in weight and body composition. Clinical sites were located in Pittsburgh, Pa, and Memphis, Tenn. Aortic pulse wave velocity was used as an indirect measure of aortic stiffness. A faster pulse wave velocity indicates a stiffer aorta. Body fat measures were evaluated with dual energy x-ray absorptiometry and computed tomography. Independent of age and blood pressure, pulse wave velocity was positively associated with weight, abdominal circumference, abdominal subcutaneous fat, abdominal visceral fat, thigh fat area, and total fat (Pwave velocity was also positively associated with history of diabetes and higher levels of glucose, insulin, and hemoglobin A1c (Pwave velocity were found for age, systolic blood pressure, heart rate, abdominal visceral fat, smoking, hemoglobin A1c, and history of hypertension. The association between pulse wave velocity and abdominal visceral fat was consistent across tertiles of body weight. Among older adults, higher levels of visceral fat are associated with greater aortic stiffness as measured by pulse wave velocity.

  14. Comparison of hybrid endovascular and open surgical repair for proximal aortic arch diseases.

    Science.gov (United States)

    Kang, Woong Chol; Ko, Young-Guk; Shin, Eak Kyun; Park, Chul-Hyun; Choi, Donghoon; Youn, Young Nam; Lee, Do Yun

    2016-01-15

    To compare the outcomes of hybrid endovascular and open surgical repair for proximal aortic arch diseases. A total of 55 consecutive patients with aortic arch aneurysm or aortic dissection involving any of zone 0 to 1 (39 male, age 63.4 ± 14.3 years) underwent a hybrid endovascular repair (n=35) or open surgical repair (n=20) from 2006 to 2014 were analyzed retrospectively. Perioperative and late outcomes were compared. Baseline characteristics were similar between the two groups, except age and EuroSCORE II, which were higher in the hybrid group. Perioperative mortality or stroke was not significantly different between the two groups, however, tended to be lower in the hybrid repair group than in the open repair group (11.4% vs. 30.0%, p=0.144). Incidences of other morbidities did not differ. During follow-up, over-all survival was similar between the hybrid and the open repair was similar (87.3% vs. 79.7% at 1 year and 83.8% vs. 72.4% at 3 years; p=0.319). However, reintervention-free survival was significantly lower for hybrid repair compared with open repair (83.8% vs. 100% at 1 year and 65.7% vs. 100% at 3 years; p=0.022). Hybrid repair of proximal aortic disease showed comparable perioperative and late outcomes compared with open surgical repair despite a higher reintervention rate during follow-up. Therefore, hybrid repair may be considered as an acceptable treatment alternative to surgery especially in patients at high surgical risk. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Acute hypotension induced by aortic clamp vs. PTH provokes distinct proximal tubule Na+ transporter redistribution patterns

    DEFF Research Database (Denmark)

    Leong, Patrick K K; Yang, Li E; Lin, Harrison W

    2004-01-01

    . This study aimed to determine the effects of acute hypotension, induced by aortic clamp or by high-dose PTH (100 microg PTH/kg), on renal hemodynamics and proximal tubule Na/H exchanger isoform 3 (NHE3) and type IIa Na-P(i) cotransporter protein (NaPi2) distribution. Subcellular distribution was analyzed...... clearance. There was, however, no significant change in glomerular filtration rate (GFR) or subcellular distribution of NHE3 and NaPi2. In contrast, high-dose PTH rapidly (

  16. Effect of beta-1-blocker, nebivolol, on central aortic pressure and arterial stiffness in patients with essential hypertension.

    Science.gov (United States)

    Soanker, Radhika; Naidu, M U R; Raju, Sree Bhushan; Prasad, A Krishna; Rao, T Ramesh Kumar

    2012-05-01

    Blood pressure (BP) reduction is the major determinant of benefit provided by antihypertensive treatment. Although different drugs reduce peripheral BP to some extent, there may be a significant difference in their effect on central BP reduction. It has been shown that beta-blockers are efficient in reducing peripheral, but not central BP. This study was done to assess the effect of beta-1-blocker, nebivolol, in patients with essential hypertension on central aortic pressures and arterial stiffness. In this single arm, open-labeled study, 13 patients were given nebivolol, 5 mg orally once daily for 15 days. Primary outcome was change in central aortic pressure, and other measures of efficacy included changes in brachial BP, augmentation index (AIx%), AIx%@75 HR, augmentation pressure (AP), heart rate (HR), and carotid femoral pulse wave velocity (PWVcf). Nebivolol 5 mg significantly reduced central aortic pressures [systolic BP, 131.5-111.6 mmHg; diastolic BP, 96.3-81.7 mmHg; Mean Arterial Pressure (MAP), 111.3-94.0 mmHg (all PPressure (PP), 35.2-29.7 mmHg (Plost to followup. Nebivolol 5 mg demonstrated antihypertensive efficacy in patients with essential hypertension by reducing not only peripheral brachial pressures, but also significantly reducing central aortic pressures, augmentation index, and carotid femoral pulse wave velocity, which is the marker of arterial stiffness.

  17. High Central Aortic Rather than Brachial Blood Pressure is Associated with Carotid Wall Remodeling and Increased Arterial Stiffness in Childhood.

    Science.gov (United States)

    Peluso, Gonzalo; García-Espinosa, Victoria; Curcio, Santiago; Marota, Marco; Castro, Juan; Chiesa, Pedro; Giachetto, Gustavo; Bia, Daniel; Zócalo, Yanina

    2017-03-01

    In adults, central blood pressure (cBP) is reported to associate target organ damages (TODs) rather than peripheral blood pressure (pBP). However, data regarding the association of pre-clinical TODs with cBP and pBP in pediatric populations are scarce. To evaluate in children and adolescents the importance of cBP and pBP levels, in terms of their association with hemodynamic and vascular changes. 315 subjects [age (mean/range) 12/8-18 years] were included. pBP (oscillometry, Omron-HEM433INT and Mobil-O-Graph), cBP levels and waveforms (oscillometry, Mobil-O-Graph; applanation tonometry, SphygmoCor), aortic wave reflection-related parameters, carotid intima-media thickness (CIMT) and carotid (elastic modulus, stiffness-index) and aortic stiffness (carotid-femoral pulse wave velocity, PWV). Four groups were defined considering pBP and cBP percentiles (th): cBP ≥90th, cBP th, pBP ≥90th, pBP th. In each group, haemodynamic and vascular parameters were compared for subgroups defined considering the level of the remaining blood pressure (cBP or pBP). Subgroups were matched for anthropometric and cardiovascular risk factors (propensity matching-score). Subjects with high cBP showed a worse cardiovascular risk profile in addition to worse peripheral hemodynamic conditions. The CIMT, carotid and aortic stiffness levels were also higher in those subjects. CIMT and carotid stiffness remained statistically higher when subjects were matched for pBP and other cardiovascular risk factors. There were no differences in arterial properties when subjects were analyzed (compared) considering similar pBP levels, during normal and high cBP conditions. Compared with pBP, the cBP levels show a greater association with vascular alterations (high CIMT and arterial stiffness), in children and adolescents.

  18. Aortic stiffness is associated with cardiac function and cerebral small vessel disease in patients with type 1 diabetes mellitus: assessment by magnetic resonance imaging

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    Elderen, Saskia G.C. van; Brandts, A.; Westenberg, J.J.M.; Grond, J. van der; Buchem, M.A. van; Kroft, L.J.M.; Roos, A. de [Leiden University Medical Center, Department of Radiology, Leiden (Netherlands); Tamsma, J.T.; Romijn, J.A.; Smit, J.W.A. [Leiden University Medical Center, Department of Endocrinology, Leiden (Netherlands)

    2010-05-15

    To evaluate, with the use of magnetic resonance imaging (MRI), whether aortic pulse wave velocity (PWV) is associated with cardiac left ventricular (LV) function and mass as well as with cerebral small vessel disease in patients with type 1 diabetes mellitus (DM). We included 86 consecutive type 1 DM patients (49 male, mean age 46.9 {+-} 11.7 years) in a prospective, cross-sectional study. Exclusion criteria included aortic/heart disease and general MRI contra-indications. MRI of the aorta, heart and brain was performed for assessment of aortic PWV, as a marker of aortic stiffness, systolic LV function and mass, as well as for the presence of cerebral white matter hyperintensities (WMHs), microbleeds and lacunar infarcts. Multivariate linear or logistic regression was performed to analyse the association between aortic PWV and outcome parameters, with covariates defined as age, gender, mean arterial pressure, heart rate, BMI, smoking, DM duration and hypertension. Mean aortic PWV was 7.1 {+-} 2.5 m/s. Aortic PWV was independently associated with LV ejection fraction (ss= -0.406, P = 0.006), LV stroke volume (ss=-0.407, P = 0.001), LV cardiac output (ss= -0.458, P = 0.001), and with cerebral WMHs (P < 0.05). There were no independent associations between aortic stiffness and LV mass, cerebral microbleeds or lacunar infarcts. Aortic stiffness is independently associated with systolic LV function and cerebral WMHs in patients with type 1 DM. (orig.)

  19. Aortic stiffness is associated with cardiac function and cerebral small vessel disease in patients with type 1 diabetes mellitus: assessment by magnetic resonance imaging

    International Nuclear Information System (INIS)

    Elderen, Saskia G.C. van; Brandts, A.; Westenberg, J.J.M.; Grond, J. van der; Buchem, M.A. van; Kroft, L.J.M.; Roos, A. de; Tamsma, J.T.; Romijn, J.A.; Smit, J.W.A.

    2010-01-01

    To evaluate, with the use of magnetic resonance imaging (MRI), whether aortic pulse wave velocity (PWV) is associated with cardiac left ventricular (LV) function and mass as well as with cerebral small vessel disease in patients with type 1 diabetes mellitus (DM). We included 86 consecutive type 1 DM patients (49 male, mean age 46.9 ± 11.7 years) in a prospective, cross-sectional study. Exclusion criteria included aortic/heart disease and general MRI contra-indications. MRI of the aorta, heart and brain was performed for assessment of aortic PWV, as a marker of aortic stiffness, systolic LV function and mass, as well as for the presence of cerebral white matter hyperintensities (WMHs), microbleeds and lacunar infarcts. Multivariate linear or logistic regression was performed to analyse the association between aortic PWV and outcome parameters, with covariates defined as age, gender, mean arterial pressure, heart rate, BMI, smoking, DM duration and hypertension. Mean aortic PWV was 7.1 ± 2.5 m/s. Aortic PWV was independently associated with LV ejection fraction (ss= -0.406, P = 0.006), LV stroke volume (ss=-0.407, P = 0.001), LV cardiac output (ss= -0.458, P = 0.001), and with cerebral WMHs (P < 0.05). There were no independent associations between aortic stiffness and LV mass, cerebral microbleeds or lacunar infarcts. Aortic stiffness is independently associated with systolic LV function and cerebral WMHs in patients with type 1 DM. (orig.)

  20. Hydration Status Is Associated with Aortic Stiffness, but Not with Peripheral Arterial Stiffness, in Chronically Hemodialysed Patients

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    Daniel Bia

    2015-01-01

    Full Text Available Background. Adequate fluid management could be essential to minimize high arterial stiffness observed in chronically hemodialyzed patients (CHP. Aim. To determine the association between body fluid status and central and peripheral arterial stiffness levels. Methods. Arterial stiffness was assessed in 65 CHP by measuring the pulse wave velocity (PWV in a central arterial pathway (carotid-femoral and in a peripheral pathway (carotid-brachial. A blood pressure-independent regional arterial stiffness index was calculated using PWV. Volume status was assessed by whole-body multiple-frequency bioimpedance. Patients were first observed as an entire group and then divided into three different fluid status-related groups: normal, overhydration, and dehydration groups. Results. Only carotid-femoral stiffness was positively associated (P<0.05 with the hydration status evaluated through extracellular/intracellular fluid, extracellular/Total Body Fluid, and absolute and relative overhydration. Conclusion. Volume status and overload are associated with central, but not peripheral, arterial stiffness levels with independence of the blood pressure level, in CHP.

  1. Association of serum adiponectin concentration with aortic arterial stiffness in chronic kidney disease: from the KNOW-CKD study.

    Science.gov (United States)

    Kim, Chang Seong; Bae, Eun Hui; Ma, Seong Kwon; Park, Sue K; Lee, Ju Yeon; Chung, Wookyung; Lee, Kyubeck; Kim, Yeong Hoon; Oh, Kook-Hwan; Ahn, Curie; Kim, Soo Wan

    2017-08-01

    High serum adiponectin levels predict all-cause and cardiovascular mortality in chronic kidney disease (CKD). However, the relationship between serum adiponectin concentration and arterial stiffness in CKD is not well established. The aim of this study was to assess this relationship by measuring pulse wave velocity (PWV) in CKD patients. Serum adiponectin concentration was measured in 716 CKD patients in the prospective KoreaN cohort study for Outcome in patients With Chronic Kidney Disease. The study group consisted of 415 men and 301 women; mean age was 53.1 years, and baseline estimated glomerular filtration rate (eGFR) was 51 ± 29 ml/min per 1.73 m 2 . Heart to femoral PWV (hfPWV) and mean brachial to ankle PWV (baPWV) served as indicators of aortic artery stiffness and arterial stiffness, respectively. Increasing quartiles of serum adiponectin levels were associated with women, lower eGFRs and body mass indices, and higher urinary albumin-creatinine ratios. Serum adiponectin concentration also correlated with hfPWV and mean baPWV, even after adjusting for age and sex. It independently associated with hfPWV (B 0.028; 95 % confidence interval, 0.004-0.051; P = 0.020) but not mean baPWV in a multivariable linear regression analysis. In a multivariable logistic regression analysis, it correlated significantly with the highest quartile of hfPWVs but not mean baPWVs. The independent and significant correlation of serum adiponectin concentration with hfPWV in CKD patients implicates adiponectin in CKD-associated aortic stiffness.

  2. Extreme-Dipper Profile, Increased Aortic Stiffness, and Impaired Subendocardial Viability in Hypertension.

    Science.gov (United States)

    Amah, Guy; Ouardani, Rahma; Pasteur-Rousseau, Adrien; Voicu, Sebastian; Safar, Michel E; Kubis, Nathalie; Bonnin, Philippe

    2017-04-01

    In treated hypertensives, extreme-dippers with stable coronary artery disease (CAD) exhibit more severe nighttime cardiac ischemia than dippers. After excluding confounding factors such as diabetes, CAD or chronic kidney disease (CKD), we assessed whether subendocardial viability, determined by the Buckberg index, was more significantly impaired in extreme-dippers than in dippers. Two hundred thirteen consecutive treated hypertensives (156 dippers, 57 extreme-dippers), were included. After 24-hour ambulatory blood pressure (BP) monitoring, patients underwent radial applanation tonometry (with determination of: subendocardial viability ratio [SEVR], central augmentation index [AIx], and pulse pressure amplification [PPamp]), carotid-femoral pulse wave velocity (cfPWV) measurement, and cycle ergometer stress testing. Extreme-dippers showed higher cfPWV (8.99 ± 2.16 vs. 8.29 ± 1.69 m/s, P = 0.014), higher AIx (29.7 ± 9.4 vs. 26.4 ± 10.4%, P = 0.042), lower PPamp (1.22 ± 0.14 vs. 1.30 ± 0.15, P < 0.001), lower SEVR (146 ± 23% vs. 157 ± 26%, P = 0.007), and lower nighttime diastolic BP (DBP) (70 ± 9 vs. 75 ± 9 mm Hg, P < 0.001) than dippers. SEVR and cfPWV were inversely correlated. Among extreme-dippers, women exhibited lower SEVR (138 ± 21% vs. 161 ± 23%, P = 0.004), PPamp (1.16 ± 0.10 vs. 1.31 ± 0.15, P < 0.001), and nighttime DBP (67 ± 8 mm Hg vs. 72 ± 8 mm Hg, P = 0.017) than men. Extreme-dipper treated hypertensives with no history of CAD, diabetes or CKD, present increased aortic stiffness and low PPamp. Furthermore, this is the first demonstration of the greater likelihood of these patients to exhibit impaired subendocardial viability compared to dippers. Extreme-dipper hypertensive patients, women in particular, may have a significantly higher risk of silent myocardial ischemia, thus justifying systematic screening. © American Journal of Hypertension, Ltd 2017. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  3. Regulation of proximal tubular cell differentiation and proliferation in primary culture by matrix stiffness and ECM components.

    Science.gov (United States)

    Chen, Wan-Chun; Lin, Hsi-Hui; Tang, Ming-Jer

    2014-09-15

    To explore whether matrix stiffness affects cell differentiation, proliferation, and transforming growth factor (TGF)-β1-induced epithelial-mesenchymal transition (EMT) in primary cultures of mouse proximal tubular epithelial cells (mPTECs), we used a soft matrix made from monomeric collagen type I-coated polyacrylamide gel or matrigel (MG). Both kinds of soft matrix benefited primary mPTECs to retain tubular-like morphology with differentiation and growth arrest and to evade TGF-β1-induced EMT. However, the potent effect of MG on mPTEC differentiation was suppressed by glutaraldehyde-induced cross-linking and subsequently stiffening MG or by an increasing ratio of collagen in the soft mixed gel. Culture media supplemented with MG also helped mPTECs to retain tubular-like morphology and a differentiated phenotype on stiff culture dishes as soft MG did. We further found that the protein level and activity of ERK were scaled with the matrix stiffness. U-0126, a MEK inhibitor, abolished the stiff matrix-induced dedifferentiation and proliferation. These data suggest that the ERK signaling pathway plays a vital role in matrix stiffness-regulated cell growth and differentiation. Taken together, both compliant property and specific MG signals from the matrix are required for the regulation of epithelial differentiation and proliferation. This study provides a basic understanding of how physical and chemical cues derived from the extracellular matrix regulate the physiological function of proximal tubules and the pathological development of renal fibrosis. Copyright © 2014 the American Physiological Society.

  4. Chest pain in patients with arterial hypertension, angiographically normal coronary arteries and stiff aorta: the aortic pain syndrome.

    Science.gov (United States)

    Stakos, Dimitrios A; Tziakas, Dimitrios N; Chalikias, George; Mitrousi, Konstantina; Tsigalou, Christina; Boudoulas, Harisios

    2013-01-01

    Arterial hypertension is often associated with a stiff aorta as a result of collagen accumulation in the aortic wall and may produce chest pain. In the present study, possible interrelationships between aortic function, collagen turnover and exercise-induced chest pain in patients with arterial hypertension and angiographically normal coronary arteries were investigated. Ninety-seven patients with arterial hypertension, angiographically normal coronary arteries and no evidence of myocardial ischemia on nuclear cardiac imaging during exercise test were studied. Of these, 43 developed chest pain during exercise (chest pain group) while 54 did not (no chest pain group). Carotid femoral pulse-wave velocity (PWVc-f) was used to assess the elastic properties of the aorta. Amino-terminal pro-peptides of pro-collagen type I, (PINP, reflecting collagen synthesis), serum telopeptides of collagen type I (CITP, reflecting collagen degradation), pro-metalloproteinase 1 (ProMMP-1), and tissue inhibitor of metalloproteinase 1 (TIMP-1, related to collagen turnover) were measured in plasma by immunoassay. The chest pain group had higher PWVc-f, higher and /CITP ratio, and lower proMMP-1/ TIMP-1 ratio compared to the no chest pain group. PWVc-f (t=2.53, p=0.02) and PINP (t=2.42, p=0.02) were independently associated with the presence of chest pain in multiple regression analysis. Patients with arterial hypertension, exercise-induced chest pain and angiographically normal coronary arteries, without evidence of exercise-induced myocardial ischemia, had a stiffer aorta compared to those without chest pain. Alterations in collagen type I turnover that favor collagen accumulation in the aortic wall may contribute to aortic stiffening and chest pain in these patients.

  5. Increased blood pressure and aortic stiffness among abusers of anabolic androgenic steroids

    DEFF Research Database (Denmark)

    Rasmussen, Jon J; Schou, Morten; Madsen, Per L

    2018-01-01

    BACKGROUND: Abuse of anabolic androgenic steroids (AAS) is prevalent among recreational athletes and adverse effects on blood pressure (BP) and arterial stiffness could be substantial. Testosterone decreases natriuretic peptides which are key components in BP-regulation and may impair BP-homeosta......BACKGROUND: Abuse of anabolic androgenic steroids (AAS) is prevalent among recreational athletes and adverse effects on blood pressure (BP) and arterial stiffness could be substantial. Testosterone decreases natriuretic peptides which are key components in BP-regulation and may impair BP...

  6. Higher Physical Activity Is Associated With Lower Aortic Stiffness but Not With Central Blood Pressure

    DEFF Research Database (Denmark)

    Laursen, Anne Sofie Dam; Hansen, Anne-Louise Smidt; Wiinberg, Niels

    2015-01-01

    .47; -0.03). Associations with central systolic blood pressure and central pulse pressure were not statistically significant. We observed no difference in central hemodynamics when substituting 1 hour sedentary behavior with 1 hour light or moderate-to-vigorous physical activity. In this relatively...... was assessed by applanation tonometry, as aortic pulse wave velocity, and central blood pressure was estimated from radial waveforms. Associations between physical activity energy expenditure and central hemodynamics were examined by linear regression. Furthermore, the consequence of substituting 1 hour...... sedentary behavior with 1 hour light or moderate-to-vigorous physical activity on central hemodynamics was examined. Median physical activity energy expenditure was 28.0 kJ/kg/d (IQR: 19.8; 38.7). A 10 kJ/kg/d higher energy expenditure was associated with 0.75% lower aortic pulse wave velocity (CI: -1...

  7. Altered diastolic function and aortic stiffness in Alzheimer’s disease

    Directory of Open Access Journals (Sweden)

    Çalık AN

    2014-07-01

    Full Text Available Ali Nazmi Çalik,3 Kazim Serhan Özcan,4 Gülbün Yüksel,2 Baris Güngör,1 Emre Arugarslan,1 Figen Varlibas,2 Ahmet Ekmekci,1 Damirbek Osmonov,1 Mustafa Adem Tatlisu,1 Mehmet Karaca,1 Osman Bolca,1 Izzet Erdinler1 1Department of Cardiology, Siyami Ersek Cardiovascular and Thoracic Surgery Center, Istanbul, Turkey; 2Department of Neurology, Haydarpasa Numune Training and Research Hospital, Istanbul, Turkey; 3Department of Cardiology, Yozgat State Hospital, Yozgat, Turkey; 4Department of Cardiology, Derince Training and Research Hospital, Kocaeli, Turkey Background: Alzheimer’s disease (AD is closely linked to cardiovascular risk factors.Methods: Echocardiographic studies were performed, including left ventricular diastolic functions, left and right atrial conduction times, and arterial stiffness parameters, namely stiffness index, pressure-strain elastic modulus, and distensibility, on 29 patients with AD and 24 age-matched individuals with normal cognitive function.Results: The peak mitral flow velocity of the early rapid filling wave (E was lower, and the peak velocity of the late filling wave caused by atrial contraction (A, deceleration time of peak E velocity, and isovolumetric relaxation time were higher in the AD group. The early myocardial peak (Ea velocity was significantly lower in AD patients, whereas the late diastolic (Aa velocity and E/Ea ratio were similar between the two groups. In Alzheimer patients, stiffness index and pressure-strain elastic modulus were higher, and distensibility was significantly lower in the AD group compared to the control. Interatrial electromechanical delay was significantly longer in the AD group.Conclusion: Our findings suggest that patients with AD are more likely to have diastolic dysfunction, higher atrial conduction times, and increased arterial stiffness compared to the controls of same sex and similar age. Keywords: diastolic dysfunction, atrial conduction timeA Letter to the Editor has been

  8. Longitudinal Changes in Segmental Aortic Stiffness Determined by Cardiac Magnetic Resonance in Children and Young Adults With Connective Tissue Disorders (the Marfan, Loeys-Dietz, and Ehlers-Danlos Syndromes, and Nonspecific Connective Tissue Disorders).

    Science.gov (United States)

    Merlocco, Anthony; Lacro, Ronald V; Gauvreau, Kimberlee; Rabideau, Nicole; Singh, Michael N; Prakash, Ashwin

    2017-10-01

    Aortic stiffness measured by cardiac magnetic resonance (CMR) in connective tissue disorder (CTD) patients has been previously shown to be abnormal and to be associated with adverse aortic outcomes. The rate of increase in aortic stiffness with normal aging has been previously described. However, longitudinal changes in aortic stiffness have not been characterized in CTD patients. We examined longitudinal changes in CMR-derived aortic stiffness in children and young adults with CTDs. A retrospective analysis of 50 children and young adults (median age, 20 years; range, 0.2 to 49; 40% age, whereas the β stiffness index increased at all aortic segments. The average rates of decline in distensibility (x10 -3  mm Hg -1 per 10-year increase in age) were 0.7, 1.3, and 1 at the AoR, ascending aorta, and descending aorta, respectively. The rates of decline in distensibility were not associated with the rates of AoR dilation or surgical AoR replacement. In conclusion, on serial CMR measurements in children and young adults with CTDs, aortic stiffness progressively increased with age, with rates of change only slightly higher than those previously reported in healthy adults. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Comparison of the Effect of Aliskiren Versus Negative Controls on Aortic Stiffness in Patients With Marfan Syndrome Under Treatment With Atenolol.

    Science.gov (United States)

    Hwang, Ji-Won; Kim, Eun Kyoung; Jang, Shin Yi; Chung, Tae-Young; Ki, Chang-Seok; Sung, Kiick; Kim, Sung Mok; Ahn, Joonghyun; Carriere, Keumhee; Choe, Yeon Hyeon; Chang, Sung-A; Kim, Duk-Kyung

    2017-11-29

    The aim of this study was to evaluate the effect of aliskiren on aortic stiffness in patients with Marfan syndrome (MS). Twenty-eight MS patients (mean age ± standard deviation: 32.6 ± 10.6 years) were recruited from November 2009 to October 2014. All patients were receiving atenolol as standard beta-blocker therapy. A prospective randomization process was performed to assign participants to either aliskiren treatment (150-300mg orally per day) or no aliskiren treatment (negative control) in an open-label design. Central aortic distensibility and central pulsed wave velocity (PWV) by magnetic resonance imaging (MRI), peripheral PWV, central aortic blood pressure and augmentation index by peripheral tonometry, and aortic dilatation by echocardiography were examined initially and after 24 weeks. The primary endpoint was central aortic distensibility by MRI. In analyses of differences between baseline and 24 weeks for the aliskiren treatment group vs the negative control group, central distensibility (overall; P = .26) and central PWV (0.2 ± 0.9 vs 0.03 ± 0.7 [m/s]; P = .79) by MRI were not significantly different. Central systolic aortic blood pressure tended to be lower by 14mmHg in patients in the aliskiren treatment group than in the control group (P = .09). A significant decrease in peripheral PWV (brachial-ankle PWV) in the aliskiren treatment group (-1.6 m/s) compared with the control group (+0.28 m/s) was noted (P = .005). Among patients with MS, the addition of aliskiren to beta-blocker treatment did not significantly improve central aortic stiffness during a 24-week period. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  10. Effect of 1-year anti-TNF-α therapy on aortic stiffness, carotid atherosclerosis, and calprotectin in inflammatory arthropathies: a controlled study.

    Science.gov (United States)

    Angel, Kristin; Provan, Sella A; Fagerhol, Magne K; Mowinckel, Petter; Kvien, Tore K; Atar, Dan

    2012-06-01

    Premature arterial stiffening and atherosclerosis are increased in patients with inflammatory arthropathies such as rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA). The proinflammatory protein calprotectin is associated with inflammatory arthropathies, vascular pathology, and acute coronary events. We examined the long-term effects of treatment with tumor necrosis factor (TNF)-α antagonists on aortic stiffness and carotid intima media thickness (CIMT) in patients with inflammatory arthropathies, and the relationships to the levels of calprotectin. Fifty-five patients with RA, AS, or PsA and a clinical indication for anti-TNF-α therapy were included and followed with regular examinations for 1 year. Thirty-six patients starting with anti-TNF-α therapy were compared with a nontreatment group of 19 patients. Examinations included assessments of aortic stiffness (aortic pulse wave velocity, aPWV), CIMT, and plasma calprotectin. After 1 year, aPWV (mean (s.d.)) was improved in the treatment group, but not in the control group (-0.54 [0.79] m/s vs. 0.06 [0.61] m/s, respectively; P = 0.004), and CIMT progression (median (quartile cut-points, 25th and 75th percentiles)) was reduced in the treatment group compared to the control group (-0.002 [-0.038, 0.030] mm vs. 0.030 [0.011, 0.043] mm, respectively; P = 0.01). In multivariable analyses, anti-TNF-α therapy over time was associated with improved aPWV (P = 0.02) and reduced CIMT progression (P = 0.04), and calprotectin was longitudinally associated with aPWV (P = 0.02). Long-term anti-TNF-α therapy improved aortic stiffness and CIMT progression in patients with inflammatory arthropathies. Calprotectin may be a soluble biomarker reflecting aortic stiffening in these patients.

  11. HIV Infection Is Not Associated With Aortic Stiffness. Traditional Cardiovascular Risk Factors Are the Main Determinants-Cross-sectional Results of INI-ELSA-BRASIL.

    Science.gov (United States)

    Moreira, Rodrigo C; Mill, José G; Grinsztejn, Beatriz; Veloso, Valdilea; Fonseca, Maria de Jesus; Griep, Rosane H; Bensenor, Isabela; Cardoso, Sandra W; Lotufo, Paulo; Chor, Dora; Pacheco, Antonio G

    2018-05-01

    Aortic stiffness measured by carotid-femoral pulse wave velocity (cf-PWV) is a marker of subclinical atherosclerosis. We propose to assess whether HIV infection is associated with arterial stiffness and their determinants in HIV-infected subjects. We compared data from an HIV cohort (644 patients, HIV+) in Rio de Janeiro with 2 groups: 105 HIV-negative (HIV-) individuals and 14,873 participants of the ELSA-Brasil study. We used multivariable linear regression to investigate factors associated with cf-PWV and whether HIV was independently associated with aortic stiffness and propensity score weighting to control for imbalances between groups. From 15,860 participants, cf-PWV was obtained in 15,622 (98.5%). Median age was 51 (interquartile range 45-58), 44.41 (35.73, 54.72), and 43.60 (36.01, 50.79) years (P ELSA-Brasil, HIV- and HIV+, respectively (P ELSA-Brasil [β = -0.05; 95% confidence interval (CI) = -0.23; P = 0.12; P = 0.52] or with the HIV- groups (β = 0.10; 95% CI = -0.10; 0, 31; P = 0.32). Traditional risk factors were associated with higher cf-PWV levels in the HIV+ group, particularly waist-to-hip ratio (β = 0.20; 95% CI = 0.10; 0.30; P < 0.001, result per one SD change). HIV infection was not associated with higher aortic stiffness according to our study. In HIV-infected subjects, the stiffness of large arteries is mainly associated with traditional risk factors and not to the HIV infection per se.

  12. Cardiac magnetic resonance based evaluation of aortic stiffness and epicardial fat volume in patients with hypertension, diabetes mellitus, and myocardial infarction.

    Science.gov (United States)

    Homsi, Rami; Sprinkart, Alois M; Gieseke, Juergen; Meier-Schroers, Michael; Yuecel, Seyrani; Fischer, Stefan; Nadal, Jennifer; Dabir, Darius; Luetkens, Julian A; Kuetting, Daniel L; Schild, Hans H; Thomas, Daniel K

    2018-01-01

    Background Aortic stiffness and epicardial fat relate to cardiovascular risk. Their relationship with each other and their role with hypertension, diabetes mellitus (DM), and myocardial infarction (MI) can be evaluated by cardiac magnetic resonance (CMR). Purpose To explore an association between aortic stiffness and epicardial as well as paracardial fat volume (EFV and ParaFV, respectively) in hypertensive patients and to relate the results to the presence of DM and MI. Material and Methods A total of 156 hypertensive and 20 non-hypertensive participants were examined at 1.5 Tesla. A 2D-velocity-encoded sequence was acquired to assess aortic pulse wave velocity (PWV in m/s) as a measure of aortic stiffness. A 3D-Dixon sequence was used to determine EFV and ParaFV. Results PWV correlated with EFV (R = 0.474; P hypertensive controls compared to hypertensive patients. EFV and PWV were significantly higher in diabetic hypertensive patients without MI (n = 19; PWV: 10.4 ± 2.9; EFV: 92.5 ± 19.3) compared to hypertension-only patients (n = 84 [no DM or MI]; EFV: 64.8 ± 25.1, PWV: 9.0 ± 2.6; P hypertensive patients. Both were increased in the presence of DM; however, only EFV was increased in the presence of MI. This may relate to the PWV lowering effect of the antihypertensive medication used by hypertensive patients and underscores the benefit of EFV assessment in this regard.

  13. Aortic Stiffness and Cardiovascular Risk in Women with Previous Gestational Diabetes Mellitus.

    Directory of Open Access Journals (Sweden)

    Tove Lekva

    Full Text Available Gestational diabetes mellitus (GDM is a significant risk factor for cardiovascular disease (CVD in later life, but the mechanism remains unclear. The aim of the study was to investigate indices of glucose metabolism, dyslipidemia, and arterial stiffness (as measured by pulse wave velocity (PWV, in women with and without a history of GDM, using both the old WHO and new IADPSG diagnostic criteria, at 5 years after the index pregnancy. Dyslipidemia and PWV were used as surrogate markers for CVD risk. The population-based prospective cohort included 300 women from the original STORK study. All participants had an oral glucose tolerance test (OGTT during pregnancy. Five years later, the OGTT was repeated along with dual-energy x-ray absorptiometry, lipid analysis, and PWV analysis. Measurements were compared between those women who did and did not have GDM based on both the WHO and IADPSG criteria. We found that women with GDM based on the old WHO criteria had higher CVD risk at 5 years than those without GDM, with markedly elevated PWV and more severe dyslipidemia (higher triglycerides (TG/HDL cholesterol ratio. After adjusting for known risk factors, the most important predictors for elevated PWV and TG/HDL-C ratio at 5-year follow-up were maternal age, BMI, GDM, systolic blood pressure, and indices of glucose metabolism in the index pregnancy. In conclusion, we found a higher risk for CVD, based on the surrogate markers PWV and TG/HDL-C ratio, at 5-year follow-up in women diagnosed with GDM in the index pregnancy when using the old WHO diagnostic criteria.

  14. Aortic Stiffness and Cardiovascular Risk in Women with Previous Gestational Diabetes Mellitus.

    Science.gov (United States)

    Lekva, Tove; Bollerslev, Jens; Norwitz, Errol R; Aukrust, Pål; Henriksen, Tore; Ueland, Thor

    2015-01-01

    Gestational diabetes mellitus (GDM) is a significant risk factor for cardiovascular disease (CVD) in later life, but the mechanism remains unclear. The aim of the study was to investigate indices of glucose metabolism, dyslipidemia, and arterial stiffness (as measured by pulse wave velocity (PWV)), in women with and without a history of GDM, using both the old WHO and new IADPSG diagnostic criteria, at 5 years after the index pregnancy. Dyslipidemia and PWV were used as surrogate markers for CVD risk. The population-based prospective cohort included 300 women from the original STORK study. All participants had an oral glucose tolerance test (OGTT) during pregnancy. Five years later, the OGTT was repeated along with dual-energy x-ray absorptiometry, lipid analysis, and PWV analysis. Measurements were compared between those women who did and did not have GDM based on both the WHO and IADPSG criteria. We found that women with GDM based on the old WHO criteria had higher CVD risk at 5 years than those without GDM, with markedly elevated PWV and more severe dyslipidemia (higher triglycerides (TG)/HDL cholesterol ratio). After adjusting for known risk factors, the most important predictors for elevated PWV and TG/HDL-C ratio at 5-year follow-up were maternal age, BMI, GDM, systolic blood pressure, and indices of glucose metabolism in the index pregnancy. In conclusion, we found a higher risk for CVD, based on the surrogate markers PWV and TG/HDL-C ratio, at 5-year follow-up in women diagnosed with GDM in the index pregnancy when using the old WHO diagnostic criteria.

  15. Targeted reduction of vascular Msx1 and Msx2 mitigates arteriosclerotic calcification and aortic stiffness in LDLR-deficient mice fed diabetogenic diets.

    Science.gov (United States)

    Cheng, Su-Li; Behrmann, Abraham; Shao, Jian-Su; Ramachandran, Bindu; Krchma, Karen; Bello Arredondo, Yoanna; Kovacs, Attila; Mead, Megan; Maxson, Robert; Towler, Dwight A

    2014-12-01

    When fed high-fat diets, male LDLR(-/-) mice develop obesity, hyperlipidemia, hyperglycemia, and arteriosclerotic calcification. An osteogenic Msx-Wnt regulatory program is concomitantly upregulated in the vasculature. To better understand the mechanisms of diabetic arteriosclerosis, we generated SM22-Cre;Msx1(fl/fl);Msx2(fl/fl);LDLR(-/-) mice, assessing the impact of Msx1+Msx2 gene deletion in vascular myofibroblast and smooth muscle cells. Aortic Msx2 and Msx1 were decreased by 95% and 34% in SM22-Cre;Msx1(fl/fl);Msx2(fl/fl);LDLR(-/-) animals versus Msx1(fl/fl);Msx2(fl/fl);LDLR(-/-) controls, respectively. Aortic calcium was reduced by 31%, and pulse wave velocity, an index of stiffness, was decreased in SM22-Cre;Msx1(fl/fl);Msx2(fl/fl);LDLR(-/-) mice vs. controls. Fasting blood glucose and lipids did not differ, yet SM22-Cre;Msx1(fl/fl);Msx2(fl/fl);LDLR(-/-) siblings became more obese. Aortic adventitial myofibroblasts from SM22-Cre;Msx1(fl/fl);Msx2(fl/fl);LDLR(-/-) mice exhibited reduced osteogenic gene expression and mineralizing potential with concomitant reduction in multiple Wnt genes. Sonic hedgehog (Shh) and Sca1, markers of aortic osteogenic progenitors, were also reduced, paralleling a 78% reduction in alkaline phosphatase (TNAP)-positive adventitial myofibroblasts. RNA interference revealed that although Msx1+Msx2 supports TNAP and Wnt7b expression, Msx1 selectively maintains Shh and Msx2 sustains Wnt2, Wnt5a, and Sca1 expression in aortic adventitial myofibroblast cultures. Thus, Msx1 and Msx2 support vascular mineralization by directing the osteogenic programming of aortic progenitors in diabetic arteriosclerosis. © 2014 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  16. Medium-Term Outcomes Following Endovascular Repair of Infrarenal Abdominal Aortic Aneurysms with an Unfavourable Proximal Neck

    International Nuclear Information System (INIS)

    Saha, Prakash; Hughes, John; Patel, Ashish S.; Donati, Tommaso; Sallam, Morad; Patel, Sanjay D.; Bell, Rachel E.; Katsanos, Konstantinos; Modarai, Bijan; Zayed, Hany A.

    2015-01-01

    PurposeThe purpose of this study was to evaluate medium-term outcomes following endovascular repair of abdominal aortic aneurysms (EVAR) with unfavourable neck anatomy using stent grafts with a 36 mm or larger proximal diameter.Materials and MethodsA retrospective review of 27 patients who underwent elective EVAR between 2006 and 2008 using a stent graft with a 36 mm or larger proximal diameter was carried out. All patients had computed tomography angiography (CTA) for procedure planning, and detailed assessment of the aneurysm neck was performed using a three-dimensional CTA workstation. Patients were followed up with CTA at 3 and 12 months and annual duplex thereafter.ResultsThe median aneurysm diameter was 7 cm, and the median aneurysm neck diameter was 31 mm. Cook Zenith stent grafts were used in all patients, with a proximal diameter of 36 mm (n = 25) and 40 mm (n = 2). Primary and assisted primary technical success rates were 74 and 93 %, respectively. The follow-up period ranged from 62 to 84 months, with a median of 72 months. 15 patients died during follow-up. Two patients died from aortic rupture, and the remaining patients died from cardiac disease (n = 4), chest sepsis (n = 6), cancer (n = 2) and renal failure (n = 1). Complications included type I endoleak (n = 5), limb occlusion (n = 2), limb stenosis (n = 2), limb kinking (n = 1), dissection of an artery (n = 1), occlusion of a femorofemoral cross-over graft (n = 1) and poor attachment of a distal limb (n = 1).ConclusionsEVAR using stent grafts in the presence of an unfavourable neck has a high risk of complications. Medium-term survival in this group is low but mainly due to patient co-morbidities

  17. Medium-Term Outcomes Following Endovascular Repair of Infrarenal Abdominal Aortic Aneurysms with an Unfavourable Proximal Neck

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Prakash, E-mail: prakash.2.saha@kcl.ac.uk; Hughes, John, E-mail: johnhughes387@rocketmail.com; Patel, Ashish S., E-mail: ashish.s.patel@kcl.ac.uk; Donati, Tommaso, E-mail: tommaso.donati@gstt.nhs.uk; Sallam, Morad, E-mail: morad.sallam@gstt.nhs.uk; Patel, Sanjay D., E-mail: sanjay.patel@gstt.nhs.uk; Bell, Rachel E. [King’s Health Partners, Department of Vascular Surgery, Guy’s and St. Thomas’ Hospitals, NHS Foundation Trust (United Kingdom); Katsanos, Konstantinos, E-mail: katsanos@med.upatras.gr [King’s Health Partners, Department of Interventional Radiology, Guy’s and St. Thomas’ Hospitals, NHS Foundation Trust (United Kingdom); Modarai, Bijan, E-mail: bijan.modarai@kcl.ac.uk; Zayed, Hany A., E-mail: hany.zayed@gstt.nhs.uk [King’s Health Partners, Department of Vascular Surgery, Guy’s and St. Thomas’ Hospitals, NHS Foundation Trust (United Kingdom)

    2015-08-15

    PurposeThe purpose of this study was to evaluate medium-term outcomes following endovascular repair of abdominal aortic aneurysms (EVAR) with unfavourable neck anatomy using stent grafts with a 36 mm or larger proximal diameter.Materials and MethodsA retrospective review of 27 patients who underwent elective EVAR between 2006 and 2008 using a stent graft with a 36 mm or larger proximal diameter was carried out. All patients had computed tomography angiography (CTA) for procedure planning, and detailed assessment of the aneurysm neck was performed using a three-dimensional CTA workstation. Patients were followed up with CTA at 3 and 12 months and annual duplex thereafter.ResultsThe median aneurysm diameter was 7 cm, and the median aneurysm neck diameter was 31 mm. Cook Zenith stent grafts were used in all patients, with a proximal diameter of 36 mm (n = 25) and 40 mm (n = 2). Primary and assisted primary technical success rates were 74 and 93 %, respectively. The follow-up period ranged from 62 to 84 months, with a median of 72 months. 15 patients died during follow-up. Two patients died from aortic rupture, and the remaining patients died from cardiac disease (n = 4), chest sepsis (n = 6), cancer (n = 2) and renal failure (n = 1). Complications included type I endoleak (n = 5), limb occlusion (n = 2), limb stenosis (n = 2), limb kinking (n = 1), dissection of an artery (n = 1), occlusion of a femorofemoral cross-over graft (n = 1) and poor attachment of a distal limb (n = 1).ConclusionsEVAR using stent grafts in the presence of an unfavourable neck has a high risk of complications. Medium-term survival in this group is low but mainly due to patient co-morbidities.

  18. Proximal thoracic aorta dimensions after continuous-flow left ventricular assist device implantation: Longitudinal changes and relation to aortic valve insufficiency.

    Science.gov (United States)

    Fine, Nowell M; Park, Soon J; Stulak, John M; Topilsky, Yan; Daly, Richard C; Joyce, Lyle D; Pereira, Naveen L; Schirger, John A; Edwards, Brooks S; Lin, Grace; Kushwaha, Sudhir S

    2016-04-01

    In this study we examined the impact of continuous-flow left ventricular assist device (CF-LVAD) support on proximal thoracic aorta dimensions. Aortic root and ascending aorta diameter were measured from serial echocardiograms before and after CF-LVAD implantation in patients with ≥6 months of support, and correlated with the development of >mild aortic valve insufficiency (AI). Of 162 patients included, mean age was 58 ± 11 years and 128 (79%) were male. Seventy-nine (63%) were destination therapy patients. Mean aortic root and ascending aorta diameters at baseline, 1 month, 6 months, 12 months and long-term follow-up (mean 2.0 ± 1.4 years) were 3.5 ± 0.4, 3.5 ± 0.3, 3.9 ± 0.3, 3.9 ± 0.2 and 4.0 ± 0.3, and 3.3 ± 0.2, 3.3 ± 0.3, 3.6 ± 0.2, 3.6 ± 0.3 and 3.6 ± 0.3 cm, respectively. Only change in aortic root diameter from 1-month to 6-month follow-up reached statistical significance (p = 0.03). Nine (6%) patients had accelerated proximal thoracic aorta expansion (>0.5 cm/year), occurring predominantly in the first 6 months after implantation. These patients were older and more likely to have hypertension and baseline proximal thoracic aorta dilation. Forty-five (28%) patients developed >mild AI at long-term follow-up, including 7 of 9 (78%) of those with accelerated proximal thoracic aorta expansion. All 7 had aortic valves that remained closed throughout the cardiac cycle, and this, along with duration of CF-LVAD support and increase in aortic root diameter, were significantly associated with developing >mild AI. CF-LVAD patients have small increases in proximal thoracic aorta dimensions that predominantly occur within the first 6 months after implantation and then stabilize. Increasing aortic root diameter was associated with AI development. Copyright © 2016 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  19. Expert consensus document on the measurement of aortic stiffness in daily practice using carotid-femoral pulse wave velocity

    NARCIS (Netherlands)

    L.M. van Bortel (Luc); S. Laurent (Stephane); P. Boutouyrie (Pierre); P. Chowienczyk (Phil); J.K. Cruickshank (Kennedy); T.L.M. de Backer (Tine); J. Filipovsky (Jan); S. Huybrechts (Sofie); F.U.S. Mattace Raso (Francesco); A.D. Protogerou (Athanase); G. Schillaci (Giuseppe); P. Segers (Patrick); S. Vermeersch (Steve); T. Weber (Thomas)

    2012-01-01

    textabstractStiffness of elastic arteries like the aorta predicts cardiovascular risk. By directly reflecting arterial stiffness, having the best predictive value for cardiovascular outcome and the ease of its measurement, carotid-femoral pulse wave velocity is now considered the gold standard for

  20. Thoracic aortic stent-graft placement combined with left subclavian artery 'chimney operation': therapeutic analysis of 15 cases with insufficient proximal anchor area

    International Nuclear Information System (INIS)

    Liu Jiayi; Huang Lianjun; Fan Zhanming; Zhang Zhaoqi

    2012-01-01

    Objective: To discuss the strategies for the management of insufficient proximal anchoring area during the performance of transluminal stent-graft placement (TSGP), and to evaluate the feasibility of intentional coverage of the left subclavian artery (LSA) together with left subclavian artery stent-graft placement by using 'chimney operation' technique. Methods: A total of 15 patients with thoracic aortic diseases complicated by insufficient proximal anchoring area, who were encountered in authors' hospital during the period from Dec. 2009 to April 2011, were enrolled in this study. The clinical data were retrospectively analyzed. The thoracic aortic diseases included aortic dissection (n=6), aortic pseudoaneurysm (n=1), aortic aneurysm (n=4) and penetrating ulcer (n=4). Of the 15 patients, the distance between the lesion and LSA anchoring site 15 mm in 2. TSGP was carried out. The ostium of LSA was intentionally and completely covered by thoracic aortic stent-graft and left subclavian artery stent-graft placement was subsequently performed. The patients were kept under observation for symptoms of cerebral and upper limb ischemia. The postoperative complications such as endoleak and the patency of LSA were assessed with angiography. Results: Thoracic aortic stent-graft placement was successfully carried out in all 15 patients. In addition, one 'chimney' stent was properly implanted in LSA in each patient. After the procedure, no complications of nervous system or severe ischemia of upper extremity occurred. Follow-up examinations performed between 5 days to 3 months after the treatment revealed that the aortic stent-graft remained in stable condition and no type Ⅰ endoleak occurred, meanwhile the blood flow in 'chimney' stent was unobstructed. Conclusion: Intentional LSA coverage with 'chimney operation' can expand the applicability of TSGP with high tolerability. It is especially useful for patients with left vertebral artery blood supply dominance or with

  1. Aortic Blood Flow Reversal Determines Renal Function: Potential Explanation for Renal Dysfunction Caused by Aortic Stiffening in Hypertension.

    Science.gov (United States)

    Hashimoto, Junichiro; Ito, Sadayoshi

    2015-07-01

    Aortic stiffness determines the glomerular filtration rate (GFR) and predicts the progressive decline of the GFR. However, the underlying pathophysiological mechanism remains obscure. Recent evidence has shown a close link between aortic stiffness and the bidirectional (systolic forward and early diastolic reverse) flow characteristics. We hypothesized that the aortic stiffening-induced renal dysfunction is attributable to altered central flow dynamics. In 222 patients with hypertension, Doppler velocity waveforms were recorded at the proximal descending aorta to calculate the reverse/forward flow ratio. Tonometric waveforms were recorded to measure the carotid-femoral (aortic) and carotid-radial (peripheral) pulse wave velocities, to estimate the aortic pressure from the radial waveforms, and to compute the aortic characteristic impedance. In addition, renal hemodynamics was evaluated by duplex ultrasound. The estimated GFR was inversely correlated with the aortic pulse wave velocity, reverse/forward flow ratio, pulse pressure, and characteristic impedance, whereas it was not correlated with the peripheral pulse wave velocity or mean arterial pressure. The association between aortic pulse wave velocity and estimated GFR was independent of age, diabetes mellitus, hypercholesterolemia, and antihypertensive medication. However, further adjustment for the aortic reverse/forward flow ratio and pulse pressure substantially weakened this association, and instead, the reverse/forward flow ratio emerged as the strongest determinant of estimated GFR (P=0.001). A higher aortic reverse/forward flow ratio was also associated with lower intrarenal forward flow velocities. These results suggest that an increase in aortic flow reversal (ie, retrograde flow from the descending thoracic aorta toward the aortic arch), caused by aortic stiffening and impedance mismatch, reduces antegrade flow into the kidney and thereby deteriorates renal function. © 2015 American Heart Association

  2. Keeping the golden mean: plant stiffness and anatomy as proximal factors driving endophytic oviposition site selection in a dragonfly.

    Science.gov (United States)

    Matushkina, Natalia; Lambret, Philippe; Gorb, Stanislav

    2016-12-01

    Oviposition site selection is a crucial component of habitat selection in dragonflies. The presence of appropriate oviposition plants at breeding waters is considered to be one of the key habitat determinants for species laying eggs endophytically. Thus, Lestes macrostigma, a species which is regarded as threatened in Europe because of its highly disjunct distribution, typically prefers to lay eggs in the sea club rush Bolboschoenus maritimus. However, little is known about how the anatomical and mechanical properties of plant tissues determine the choice of L. macrostigma females. We examined green shoots of six plant species used by L. macrostigma for oviposition, either in the field (actual oviposition plants) or under experimental conditions (potential oviposition plants), to analyse anatomical and mechanical properties of shoots in a framework of known preferences regarding plant substrates for oviposition. As expected, the anatomy of shoots differed between representatives of two plant families, Cyperaceae and Juncaceae, most essentially in the distribution of supporting bundles and the presence of large aeriferous cavities that may affect egg placing within a shoot. The force necessary to puncture the tested plant samples ranged from 360 to 3298 mN, and their local stiffness ranged from 777 to 3363N/m. We show that the shoots of B. maritimus, the plant most preferred by L. macrostigma, have intermediate characteristics regarding both the stiffness and specific anatomical characteristics. The bending stiffness of the ovipositor in L. macrostigma was estimated as 1414N/m, one of the highest values recorded for zygopteran dragonflies so far. The ecological and behavioural implications of plant choice mechanisms in L. macrostigma are discussed in the context of the disjunct distribution of this species. Copyright © 2016 Elsevier GmbH. All rights reserved.

  3. The L-arginine/asymmetric dimethylarginine ratio is improved by anti-tumor necrosis factor-α therapy in inflammatory arthropathies. Associations with aortic stiffness.

    Science.gov (United States)

    Angel, Kristin; Provan, Sella Aarrestad; Mowinckel, Petter; Seljeflot, Ingebjørg; Kvien, Tore Kristian; Atar, Dan

    2012-11-01

    Anti-Tumor Necrosis Factor (TNF)-α therapy improves vascular pathology in inflammatory arthropathies such as rheumatoid arthritis, ankylosing spondylitis and psoriatic arthritis. The l-arginine/ADMA ratio is important for modulation of the nitric oxide synthase activity. We examined the effect of TNF-α antagonists on ADMA and l-arginine/ADMA, and associations between ADMA, L-arginine/ADMA, aortic stiffness and carotid intima media thickness (CIMT) in patients with inflammatory arthropathies. Forty-eight patients who started with anti-TNF-α therapy were compared with a non-treated group of 32 patients. Plasma ADMA and L-arginine were assessed at baseline, 3 and 12 months. In a subgroup of 55 patients, aortic pulse wave velocity (aPWV) was measured at baseline, 3 and 12 moths, and CIMT was examined at baseline and 12 months. Anti-TNF-α therapy increased the L-arginine/ADMA ratio (mean [SD]) in the treatment group compared to the control group after 3 months (12 [29] vs. -13 [20], P < 0.001) and 12 months (7 [27] vs. -8 [19], P = 0.008), but did not affect ADMA (3 months: 0.00 [0.09] μmol/L vs. 0.02 [0.07] μmol/L, P = 0.42, 12 months: 0.01 [0.08] μmol/L vs. 0.01 [0.09] μmol/L, P = 0.88). Baseline aPWV was associated with ADMA (P = 0.02) and L-arginine/ADMA (P = 0.02) in multiple regression analyses, and the L-arginine/ADMA ratio was continuously associated with aPWV after initiation of anti-TNF-α therapy (P = 0.03). ADMA and L-arginine/ADMA were not correlated with CIMT. Anti-TNF-α therapy improved the L-arginine/ADMA ratio in patients with inflammatory arthropathies. ADMA and the L-arginine/ADMA ratio were associated with aPWV, and might have a mechanistic role in the aortic stiffening observed in these patients. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  4. Influence of Distal Resistance and Proximal Stiffness on Hemodynamics and RV Afterload in Progression and Treatments of Pulmonary Hypertension: A Computational Study with Validation Using Animal Models

    Directory of Open Access Journals (Sweden)

    Zhenbi Su

    2013-01-01

    Full Text Available We develop a simple computational model based on measurements from a hypoxic neonatal calf model of pulmonary hypertension (PH to investigate the interplay between vascular and ventricular measures in the setting of progressive PH. Model parameters were obtained directly from in vivo and ex vivo measurements of neonatal calves. Seventeen sets of model-predicted impedance and mean pulmonary arterial pressure (mPAP show good agreement with the animal measurements, thereby validating the model. Next, we considered a predictive model in which three parameters, PVR, elastic modulus (EM, and arterial thickness, were varied singly from one simulation to the next to study their individual roles in PH progression. Finally, we used the model to predict the individual impacts of clinical (vasodilatory and theoretical (compliance increasing PH treatments on improving pulmonary hemodynamics. Our model (1 displayed excellent patient-specific agreement with measured global pulmonary parameters; (2 quantified relationships between PVR and mean pressure and PVS and pulse pressure, as well as studiying the right ventricular (RV afterload, which could be measured as a hydraulic load calculated from spectral analysis of pulmonary artery pressure and flow waves; (3 qualitatively confirmed the derangement of vascular wall shear stress in progressive PH; and (4 established that decreasing proximal vascular stiffness through a theoretical treatment of reversing proximal vascular remodeling could decrease RV afterload.

  5. Left atrium volume index is influenced by aortic stiffness and central pulse pressure in type 2 diabetes mellitus patients: a hemodynamic and echocardiographic study.

    Science.gov (United States)

    Zapolski, Tomasz; Wysokiński, Andrzej

    2013-03-04

    Left atrial volume index (LAVI) has recently emerged as a useful biomarker for risk stratification and risk monitoring in many clinical settings. Many hemodynamic factors such as preload and afterload have an effect on evaluating left atrium function. This study was performed to investigate the relationship between LAVI and aortic stiffness index (ASI) and selected markers characterizing hemodynamic state in patients with type 2 diabetes mellitus (DM2). The study population consisted of 100 patients (56 men, 44 women), 67.2 (±10.9) years old DM2, scheduled for routine coronary angiography. Standard transthoracic echocardiography was used to measure parameters needed for calculation of LAVI and ASI. During invasive procedures, central pulse pressure (CPP) in the ascendens aorta and left ventricle end-diastolic pressure (LVEDP) were recorded. Selected laboratory parameters were obtained, including lipidogram, serum uric acid, hs-CRP, fibrinogen, cTnT, myoglobin, BNP, HbA1C, creatinine, and GFR. Both LAVI and ASI were greater and CPP and LVEDP were markedly elevated in DM2 patients compared to controls. The independent predictors of LAVI were ASI (ß=0.331; p=0.011), CPP (ß=0.312; p=0.020), LVEDP (ß=0.381; p=0.006), HbA1C (ß=0.379; p=0.008), and BNP (ß=0,423; pDM2 patients.

  6. Midterm outcome of EndoAnchors for the prevention of endoleak and stent-graft migration in patients with challenging proximal aortic neck anatomy.

    Science.gov (United States)

    Jordan, William D; de Vries, Jean-Paul P M; Ouriel, Kenneth; Mehta, Manish; Varnagy, David; Moore, William M; Arko, Frank R; Joye, James; Henretta, John

    2015-04-01

    To explore the use of EndoAnchors as an adjunct to endovascular abdominal aortic aneurysm repair for prevention of proximal neck complications in patients with challenging neck anatomy. Over a 28-month period, 208 patients (159 men; mean age 72±8 years) were enrolled in the ANCHOR prospective, multicenter registry (ClinicalTrials.gov; identifier NCT01534819) for prophylaxis against proximal neck complications. Patients were eligible when, in the opinion of the investigators, they were at increased risk for type Ia endoleak or migration owing to a hostile neck (length 28 mm, angulation >60°, mural thrombus or calcium >2 mm in thickness or >180° in circumference, or conical shape). Overall, 123/157 (78.3%) patients met the criteria for a hostile neck according to core laboratory assessment of 157 adequate preoperative computed tomographic (CT) images. Implantation of EndoAnchors was technically successful in 204/208 (98.1%) patients. The frequency of fracture was 0.3% (3/1118); there were no clinical sequelae associated with the fractures. Over the mean 14-month follow-up, 95.2% of patients were alive, and no deaths were attributable to EndoAnchors. There were no ruptures, migrations, or open surgical conversions. Aneurysm-related reinterventions were performed in 8 (3.8%) patients. Among 130 patients with postprocedure contrast CT studies, core laboratory analysis identified 2 (1.5%) patients with type Ia endoleaks. Aneurysm sac diameter decreased >5 mm in 42.9% of patients with CT scans at or beyond 1 year; 1.6% of patients developed sac enlargement >5 mm. Prophylactic EndoAnchor use for challenging aortic neck anatomy was associated with satisfactory midterm results. © The Author(s) 2015.

  7. Mitochondrial oxidative stress in aortic stiffening with age: the role of smooth muscle cell function.

    Science.gov (United States)

    OBJECTIVE: Age-related aortic stiffness is an independent risk factor for cardiovascular diseases. Although oxidative stress is implicated in aortic stiffness, the underlying molecular mechanisms remain unelucidated. Here, we examined the source of oxidative stress in aging and i...

  8. Arterial stiffness

    Directory of Open Access Journals (Sweden)

    Ursula Quinn

    2012-09-01

    Full Text Available Measurements of biomechanical properties of arteries have become an important surrogate outcome used in epidemiological and interventional cardiovascular research. Structural and functional differences of vessels in the arterial tree result in a dampening of pulsatility and smoothing of blood flow as it progresses to capillary level. A loss of arterial elastic properties results a range of linked pathophysiological changes within the circulation including increased pulse pressure, left ventricular hypertrophy, subendocardial ischaemia, vessel endothelial dysfunction and cardiac fibrosis. With increased arterial stiffness, the microvasculature of brain and kidneys are exposed to wider pressure fluctuations and may lead to increased risk of stroke and renal failure. Stiffening of the aorta, as measured by the gold-standard technique of aortic Pulse Wave Velocity (aPWV, is independently associated with adverse cardiovascular outcomes across many different patient groups and in the general population. Therefore, use of aPWV has been proposed for early detection of vascular damage and individual cardiovascular risk evaluation and it seems certain that measurement of arterial stiffness will become increasingly important in future clinical care. In this review we will consider some of the pathophysiological processes that result from arterial stiffening, how it is measured and factors that may drive it as well as potential avenues for therapy. In the face of an ageing population where mortality from atheromatous cardiovascular disease is falling, pathology associated with arterial stiffening will assume ever greater importance. Therefore, understanding these concepts for all clinicians involved in care of patients with cardiovascular disease will become vital.

  9. Is chronic obstructive pulmonary disease associated with increased arterial stiffness?

    DEFF Research Database (Denmark)

    Janner, Julie H; McAllister, David A; Godtfredsen, Nina S

    2012-01-01

    We hypothesize that airflow limitation is associated with increasing arterial stiffness and that having COPD increases a non-invasive measure of arterial stiffness - the aortic augmentation index (AIx) - independently of other CVD risk factors.......We hypothesize that airflow limitation is associated with increasing arterial stiffness and that having COPD increases a non-invasive measure of arterial stiffness - the aortic augmentation index (AIx) - independently of other CVD risk factors....

  10. Targeted Reduction of Vascular Msx1 and Msx2 Mitigates Arteriosclerotic Calcification and Aortic Stiffness in LDLR-Deficient Mice Fed Diabetogenic Diets

    OpenAIRE

    Cheng, Su-Li; Behrmann, Abraham; Shao, Jian-Su; Ramachandran, Bindu; Krchma, Karen; Bello Arredondo, Yoanna; Kovacs, Attila; Mead, Megan; Maxson, Robert; Towler, Dwight A.

    2014-01-01

    When fed high-fat diets, male LDLR?/? mice develop obesity, hyperlipidemia, hyperglycemia, and arteriosclerotic calcification. An osteogenic Msx-Wnt regulatory program is concomitantly upregulated in the vasculature. To better understand the mechanisms of diabetic arteriosclerosis, we generated SM22-Cre;Msx1(fl/fl);Msx2(fl/fl);LDLR?/? mice, assessing the impact of Msx1+Msx2 gene deletion in vascular myofibroblast and smooth muscle cells. Aortic Msx2 and Msx1 were decreased by 95% and 34% in S...

  11. A insuficiência da valva aórtica na dissecção crônica da aorta proximal: troca ou reconstrução valvar? Aortic valve insufficiency in chronic aortic dissection: valve replacement or reconstruction?

    Directory of Open Access Journals (Sweden)

    Ricardo Beyruti

    1993-06-01

    Full Text Available Com o objetivo de avaliar os resultados clínicos e ecocardiográficos tardios obtidos com a correção da insuficiência aórtica decorrente da dissecção crônica da aorta proximal, foram estudados 48 pacientes consecutivos operados entre janeiro de 1980 e dezembro de 1989, separados em 2 grupos de 24 pacientes cada. Grupo A - pacientes nos quais a valva aórtica foi preservada pela "resuspensão comissural"; Grupo B - pacientes nos quais a valva aórtica foi substituída. Na avaliação ecocardiográfica pré-operatória, os pacientes do Grupo B apresentavam grau de insuficiência aórtica, diâmetros ventriculares (sistólico e diastólico e da aorta ascendente significativamente maiores do que os do Grupo A (p=0,03, sendo comparáveis nos demais parâmetros. A mortalidade hospitalar foi 12,5% no Grupo A e de 4,17% no Grupo B e a sobrevida aos 7 anos, respectivamente, 75,75% ± 9,82% e 82,72% ± 7,87% (NS. A avaliação clínica mostrou que, no pós-operatório, houve melhora significativa (pFrom January 1980 to December 1989, 48 consecutive patients with chronic aortic dissection and aortic valve insufficiency underwent operation. They were analyzed in 2 groups (24 patients each to evaluate the late clinical and echocardiography outcome of those in whom the aortic valve was preserved (Group A compared with those having valve replacement (Group B. The overall preoperative characteristics of the two groups were similar except for the age (Group A 47.9 ± 10.8 versus Group B 40.2 ± 9.5 years, p=0.03. In the preoperative echocardiographic evaluation, Group B patients had significantly higher aortic root and left ventricle systolic and diastolic diameters (p<0.03, and aortic insufficiency grade (p=0.02. The hospital mortality was 12.5% in Group A and 4.2% in Group B and the seven years actuarial survival rate was respectively 75.7% ± 9.8% and 82.7% ± 7.9%. Postoperatively there was, in both groups, a significant improvement in all clinical

  12. Aortic insufficiency

    Science.gov (United States)

    ... page, please enable JavaScript. Aortic insufficiency is a heart valve disease in which the aortic valve does not close ... aortic insufficiency Images Aortic insufficiency References Carabello BA. Valvular heart disease. In: Goldman L, Schafer AI, eds. Goldman-Cecil ...

  13. [Aortic elastic properties and its clinical significance in intracranial aneurysms].

    Science.gov (United States)

    Pu, Zhao-xia; You, Xiang-dong; Weng, Wen-chao; Wang, Jian-an; Shi, Jian

    2011-09-01

    To investigate the aortic elastic properties and its clinical significance in intracranial aneurysms (IAs). One hundred and seven IAs patients (57 with hypertension) and 108 healthy subjects were recruited. The internal aortic diameters in systole and diastole were measured by the M-mode echocardiography, the aortic elasticity indexes were calculated and compared. The aortic distensibility (DIS) was lower and the aortic stiffness index (SI) was higher in IAs patients than those in controls (both P IAs patients with hypertension (IAs-HP) than those in IAs with no hypertension (P IAs patients and hypertension is closely related to the severity of aortic elasticity.

  14. Traumatic Aortic Injury

    Directory of Open Access Journals (Sweden)

    Brianna Miner

    2016-09-01

    Full Text Available History of present illness: A 48-year-old male with unknown past medical history presents as a trauma after being hit by a car traveling approximately 25 miles per hour. On initial presentation, the patient is confused, combative, and not answering questions appropriately. The patient is hypotensive with a blood pressure of 68/40 and a heart rate of 50 beats per minute, with oxygen saturation at 96% on room air. FAST scan is positive for fluid in Morrison’s pouch, splenorenal space, and pericardial space. Significant findings: The initial chest x-ray showed an abnormal superior mediastinal contour (blue line, suggestive of a possible aortic injury. The CT angiogram showed extensive circumferential irregularity and outpouching of the distal aortic arch (red arrows compatible with aortic transection. In addition, there was a circumferential intramural hematoma, which extended through the descending aorta to the proximal infrarenal abdominal aorta (green arrow. There was also an extensive surrounding mediastinal hematoma extending around the descending aorta and supraaortic branches (purple arrows. Discussion: Traumatic aortic injury is a life-threatening event. The incidence of blunt thoracic aortic injury is low, between 1 to 2 percent of those patients with blunt thoracic trauma.1 However, approximately 80% of patients with traumatic aortic injury die at the scene.2 Therefore it is imperative to diagnose traumatic aortic injury in a timely fashion. The diagnosis can be difficult due to the non-specific signs and symptoms and other distracting injuries. Clinical suspicion should be based on the mechanism of the injury and the hemodynamic status of the patient. In any patient with blunt or penetrating trauma to the chest that is hemodynamically unstable, traumatic aortic injury should be on the differential. Chest x-ray can be used as a screening tool. A normal chest x-ray has a negative predictive value of approximately 97%. CTA chest is the

  15. Aortopathy in Congenital Heart Disease in Adults: Aortic Dilatation with Decreased Aortic Elasticity that Impacts Negatively on Left Ventricular Function.

    Science.gov (United States)

    Niwa, Koichiro

    2013-04-01

    Bicuspid aortic valve and/or coarctation of the aorta are consistently associated with ascending aortic and para-coarctation medial abnormalities. Medial abnormalities in the ascending aorta are prevalent in other types of patients with a variety of forms congenital heart disease (CHD), such as single ventricle, persistent truncus arteriosus, transposition of the great arteries, hypoplastic left heart syndrome, tetralogy of Fallot. These abnormalities encompass a wide age range, and may predispose to dilatation, aneurysm, and rupture that necessitates aortic valve and root surgery. This dilatation can develop in CHD patients without stenotic region. These CHDs exhibit ongoing dilatation of the aortic root and reduced aortic elasticity and increased aortic stiffness that may relate to intrinsic properties of the aortic root. The concept of aortic dilatation is shifting a paradigm of aortic dilatation, as so called post stenotic dilatation, to primary intrinsic aortopahy. These aortic dilatation and increased stiffness can induce aortic aneurysm, rupture of the aorta and aortic regurgitation, but also provoke left ventricular hypertrophy, reduced coronary artery flow and left ventricular failure. We can recognize this association of aortic pathophysiological abnormality, aortic dilation and aorto-left ventricular interaction as a new clinical entity: "aortopathy".

  16. Stiff Hands

    Science.gov (United States)

    ... All Topics A-Z Videos Infographics Symptom Picker Anatomy Bones Joints Muscles Nerves Vessels Tendons About Hand Surgery What is a Hand Surgeon? What is a Hand Therapist? Media Find a Hand Surgeon Home Anatomy Stiff Hands Email to a friend * required fields ...

  17. Physiologic Tolerance of Descending Thoracic Aortic Balloon Occlusion in a Swine Model of Hemorrhagic Shock

    Science.gov (United States)

    2013-01-10

    Endovascular proximal control of ruptured abdominal aortic aneurysms: the internal aortic clamp. J Cardiovasc Surg (Torino) 2009;50(3):381. 14. Arthurs Z...Starnes B, See C, Andersen C. Clamp Before You Cut: Proximal Control of Ruptured Abdominal Aortic Aneurysms Using Endovascular Balloon Occlusion

  18. Hemodynamic and Mechanical Properties of the Proximal Aorta in Young and Middle-Aged Adults With Isolated Systolic Hypertension: The Dallas Heart Study.

    Science.gov (United States)

    Yano, Yuichiro; Neeland, Ian J; Ayers, Colby; Peshock, Ronald; Berry, Jarett D; Lloyd-Jones, Donald M; Greenland, Philip; Mitchell, Gary F; Vongpatanasin, Wanpen

    2017-07-01

    The aim of this study was to assess characteristic impedance (Z c ) of the proximal aorta in young and middle-aged individuals with isolated systolic hypertension (ISH). Z c is an index of aortic stiffness relative to aortic size. In the Dallas Heart Study, 2001 untreated participants 18 to 64 years of age (mean age: 42.3 years; 44% black race) were divided into the following groups based on office blood pressure (BP) measurements: (1) optimal BP (systolic BP [SBP] hypertension (SBP hypertension (SBP ≥140 mm Hg and DBP ≥90 mm Hg; n=178). Z c , aortic arch pulse wave velocity, and minimum ascending aortic size were quantified using cardiovascular magnetic resonance. In multivariable-adjusted linear models, Z c was highest in the ISH group compared with the optimal BP, isolated diastolic hypertension, or systolic-diastolic hypertension groups (103.2±4.0 versus 68.3±2.1, 75.4±6.0, and 88.9±4.8 dyne*seconds/cm 5 , respectively; all P hypertension, or systolic-diastolic hypertension groups (6.3±0.3 versus 4.3±0.1, 4.4±0.4 and 5.5±0.3 m/s, respectively; all P 0.2). Results were similar in a subgroup of 1551 participants 18 to 49 years of age. In a multiracial population-based sample, we found evidence of a mismatch between proximal aortic stiffness and diameter in young and middle-aged adults with ISH. © 2017 American Heart Association, Inc.

  19. Stroke Volume estimation using aortic pressure measurements and aortic cross sectional area: Proof of concept.

    Science.gov (United States)

    Kamoi, S; Pretty, C G; Chiew, Y S; Pironet, A; Davidson, S; Desaive, T; Shaw, G M; Chase, J G

    2015-08-01

    Accurate Stroke Volume (SV) monitoring is essential for patient with cardiovascular dysfunction patients. However, direct SV measurements are not clinically feasible due to the highly invasive nature of measurement devices. Current devices for indirect monitoring of SV are shown to be inaccurate during sudden hemodynamic changes. This paper presents a novel SV estimation using readily available aortic pressure measurements and aortic cross sectional area, using data from a porcine experiment where medical interventions such as fluid replacement, dobutamine infusions, and recruitment maneuvers induced SV changes in a pig with circulatory shock. Measurement of left ventricular volume, proximal aortic pressure, and descending aortic pressure waveforms were made simultaneously during the experiment. From measured data, proximal aortic pressure was separated into reservoir and excess pressures. Beat-to-beat aortic characteristic impedance values were calculated using both aortic pressure measurements and an estimate of the aortic cross sectional area. SV was estimated using the calculated aortic characteristic impedance and excess component of the proximal aorta. The median difference between directly measured SV and estimated SV was -1.4ml with 95% limit of agreement +/- 6.6ml. This method demonstrates that SV can be accurately captured beat-to-beat during sudden changes in hemodynamic state. This novel SV estimation could enable improved cardiac and circulatory treatment in the critical care environment by titrating treatment to the effect on SV.

  20. Concepts to optimize stent-grafting of abdominal aortic aneurysms based on results of experimental studies

    International Nuclear Information System (INIS)

    Chavan, A.; Kirchhoff, T.; Baus, S.; Galanski, M.; Pichlmaier, M.

    2001-01-01

    Purpose. In the endoluminal therapy of abdominal aortic aneurysms, a short proximal aneurysm neck, endoleaks and the large size and stiffness of the introducer systems are responsible for many of the complications and sub-optimal outcomes. The purpose of the present review article is to to suggest strategies to minimize these complications based on the results of experimental studies in animals. Material and methods. After implanting various types of stents across the renal artery origins, the functional and morphological changes in the kidneys and renal vessels were studied by various authors. In order to prevent progressive widening of the proximal aneurysmal neck and graft dislocation, Sonesson et al. performed a laparoscopic banding around the proximal neck in pigs. To study the effects of endoleaks, Marty, Schurink and Pitton carried out pressure measurements in experimental aneurysms with and without endoleaks. Sakaguchi and Pavcnik developed the 'Twin-tube endografts' (TTEG) and the 'Bifurcated drum occluder endografts' (BDOEG) and tested them in dogs. Results. Up to 3 months after suprarenal stent placement, Chavan et al. detected no significant fall in the mean inulin clearance in sheep (140±46 ml/min before, 137±58 ml/min after). Nasim et al. and Malina et al. reported similar observations with respect to renal function. Suprarenal fixation may result in isolated thrombotic occlusions of the renal arteries and microinfarcts in the kidneys. Mean aortic diameters at the level of banding were significantly smaller in the animals with aortic banding as opposed to those in the control group without banding (8 mm vs 11 mm, p=0.004). The banding caused a secure proximal fixation of the stent-graft. Persistent endoleaks resulted in significantly higher intraaneurysmal pressures. Although the TTEG and the BDOEG stent-grafts required smaller sheaths, occlusions were observed in 8% (TTEG) and 60% (BDOEG) of the graft limbs. (orig.) [de

  1. Geometric Deformations of the Thoracic Aorta and Supra-Aortic Arch Branch Vessels Following Thoracic Endovascular Aortic Repair.

    Science.gov (United States)

    Ullery, Brant W; Suh, Ga-Young; Hirotsu, Kelsey; Zhu, David; Lee, Jason T; Dake, Michael D; Fleischmann, Dominik; Cheng, Christopher P

    2018-04-01

    To utilize 3-D modeling techniques to better characterize geometric deformations of the supra-aortic arch branch vessels and descending thoracic aorta after thoracic endovascular aortic repair. Eighteen patients underwent endovascular repair of either type B aortic dissection (n = 10) or thoracic aortic aneurysm (n = 8). Computed tomography angiography was obtained pre- and postprocedure, and 3-D geometric models of the aorta and supra-aortic branch vessels were constructed. Branch angle of the supra-aortic branch vessels and curvature metrics of the ascending aorta, aortic arch, and stented thoracic aortic lumen were calculated both at pre- and postintervention. The left common carotid artery branch angle was lower than the left subclavian artery angles preintervention ( P Supra-aortic branch vessel angulation remains relatively static when proximal landing zones are distal to the left common carotid artery.

  2. Arterial wave reflection and aortic valve calcification in an elderly community-based cohort.

    Science.gov (United States)

    Sera, Fusako; Russo, Cesare; Iwata, Shinichi; Jin, Zhezhen; Rundek, Tatjana; Elkind, Mitchell S V; Homma, Shunichi; Sacco, Ralph L; Di Tullio, Marco R

    2015-04-01

    Aortic valve calcification (AVC) without stenosis is common in the elderly, is associated with cardiovascular morbidity and mortality, and may progress to aortic valve stenosis. Arterial stiffness and pulse-wave reflection are important components of proximal aortic hemodynamics, but their relationship with AVC is not established. To investigate the relationship of arterial wave reflection and stiffness with AVC, pulse wave analysis and AVC evaluation by echocardiography were performed in 867 participants from the Cardiovascular Abnormalities and Brain Lesions study. Participants were divided into four categories on the basis of the severity and extent of AVC: (1) none or mild focal AVC, (2) mild diffuse AVC, (3) moderate to severe focal AVC, and (4) moderate to severe diffuse AVC. Central blood pressures and pulse pressure, total arterial compliance, augmentation index, and time to wave reflection were assessed using applanation tonometry. Indicators of arterial stiffness and wave reflection were significantly associated with AVC severity, except for central systolic and diastolic pressures and time to reflection. After adjustment for pertinent covariates (age, sex, race/ethnicity, and estimated glomerular filtration rate), only augmentation pressure (P = .02) and augmentation index (P = .002) were associated with the severity of AVC. Multivariate logistic regression analysis revealed that augmentation pressure (odds ratio per mm Hg, 1.14; 95% confidence interval, 1.02-1.27; P = .02) and augmentation index (odds ratio per percentage point, 1.07; 95% confidence interval, 1.01-1.13; P = .02) were associated with an increased risk for moderate to severe diffuse AVC, even when central blood pressure value was included in the same model. Arterial wave reflection is associated with AVC severity, independent of blood pressure values. Increased contribution of wave reflection to central blood pressure could be involved in the process leading to AVC. Copyright © 2015

  3. Reoperative Aortic Root Replacement in Patients with Previous Aortic Root or Aortic Valve Procedures

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    Byung Kwon Chong

    2016-08-01

    Full Text Available Background: Generalization of standardized surgical techniques to treat aortic valve (AV and aortic root diseases has benefited large numbers of patients. As a consequence of the proliferation of patients receiving aortic root surgeries, surgeons are more frequently challenged by reoperative aortic root procedures. The aim of this study was to evaluate the outcomes of redo-aortic root replacement (ARR. Methods: We retrospectively reviewed 66 patients (36 male; mean age, 44.5±9.5 years who underwent redo-ARR following AV or aortic root procedures between April 1995 and June 2015. Results: Emergency surgeries comprised 43.9% (n=29. Indications for the redo-ARR were aneurysm (n=12, pseudoaneurysm (n=1, or dissection (n=6 of the residual native aortic sinus in 19 patients (28.8%, native AV dysfunction in 8 patients (12.1%, structural dysfunction of an implanted bioprosthetic AV in 19 patients (28.8%, and infection of previously replaced AV or proximal aortic grafts in 30 patients (45.5%. There were 3 early deaths (4.5%. During follow- up (median, 54.65 months; quartile 1–3, 17.93 to 95.71 months, there were 14 late deaths (21.2%, and 9 valve-related complications including reoperation of the aortic root in 1 patient, infective endocarditis in 3 patients, and hemorrhagic events in 5 patients. Overall survival and event-free survival rates at 5 years were 81.5%±5.1% and 76.4%±5.4%, respectively. Conclusion: Despite technical challenges and a high rate of emergency conditions in patients requiring redo-ARR, early and late outcomes were acceptable in these patients.

  4. Aortic stenosis

    Science.gov (United States)

    ... Images Aortic stenosis Heart valves References Carabello BA. Valvular heart disease. In: Goldman L, Schafer AI, eds. Goldman-Cecil ... ACC guideline for the management of patients with valvular heart disease: a report of the American College of Cardiology/ ...

  5. Ultrasonic delineation of aortic microstructure: The relative contribution of elastin and collagen to aortic elasticity

    Science.gov (United States)

    Marsh, Jon N.; Takiuchi, Shin; Lin, Shiow Jiuan; Lanza, Gregory M.; Wickline, Samuel A.

    2004-05-01

    Aortic elasticity is an important factor in hemodynamic health, and compromised aortic compliance affects not only arterial dynamics but also myocardial function. A variety of pathologic processes (e.g., diabetes, Marfan's syndrome, hypertension) can affect aortic elasticity by altering the microstructure and composition of the elastin and collagen fiber networks within the tunica media. Ultrasound tissue characterization techniques can be used to obtain direct measurements of the stiffness coefficients of aorta by measurement of the speed of sound in specific directions. In this study we sought to define the contributions of elastin and collagen to the mechanical properties of aortic media by measuring the magnitude and directional dependence of the speed of sound before and after selective isolation of either the collagen or elastin fiber matrix. Formalin-fixed porcine aortas were sectioned for insonification in the circumferential, longitudinal, or radial direction and examined using high-frequency (50 MHz) ultrasound microscopy. Isolation of the collagen or elastin fiber matrices was accomplished through treatment with NaOH or formic acid, respectively. The results suggest that elastin is the primary contributor to aortic medial stiffness in the unloaded state, and that there is relatively little anisotropy in the speed of sound or stiffness in the aortic wall.

  6. Reverse extra-anatomic aortic arch debranching procedure allowing thoracic endovascular aortic repair of a chronic ascending aortic aneurysm

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    Ludovic Canaud, MD, PhD

    2018-06-01

    Full Text Available A 79-year-old woman was admitted with a large chronic dissecting ascending aortic aneurysm starting 5 mm distal to the ostia of the left coronary artery and ending immediately proximal to the innominate artery. A reverse extra-anatomic aortic arch debranching procedure was performed. During the same operative time, through a transapical approach, a thoracic stent graft was deployed with the proximal landing zone just distal to the coronary ostia and the distal landing zone excluding the origin of the left common carotid artery. The postoperative course was uneventful. Computed tomography at 12 months documented patent extra-anatomic aortic arch debranching and no evidence of endoleak. Keywords: Ascending aorta, Thoracic aorta, Aortic dissection, Stent graft

  7. Hemodynamic and arterial stiffness differences between African-Americans and Caucasians after maximal exercise.

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    Yan, Huimin; Ranadive, Sushant M; Heffernan, Kevin S; Lane, Abbi D; Kappus, Rebecca M; Cook, Marc D; Wu, Pei-Tzu; Sun, Peng; Harvey, Idethia S; Woods, Jeffrey A; Wilund, Kenneth R; Fernhall, Bo

    2014-01-01

    African-American (AA) men have higher arterial stiffness and augmentation index (AIx) than Caucasian-American (CA) men. Women have greater age-associated increases in arterial stiffness and AIx than men. This study examined racial and sex differences in arterial stiffness and central hemodynamics at rest and after an acute bout of maximal exercise in young healthy individuals. One hundred young, healthy individuals (28 AA men, 24 AA women, 25 CA men, and 23 CA women) underwent measurements of aortic blood pressure (BP) and arterial stiffness at rest and 15 and 30 min after an acute bout of graded maximal aerobic exercise. Aortic BP and AIx were derived from radial artery applanation tonometry. Aortic stiffness (carotid-femoral) was measured via pulse wave velocity. Aortic stiffness was increased in AA subjects but not in CA subjects (P < 0.05) after an acute bout of maximal cycling exercise, after controlling for body mass index. Aortic BP decreased after exercise in CA subjects but not in AA subjects (P < 0.05). Women exhibited greater reductions in AIx after maximal aerobic exercise compared with men (P < 0.05). In conclusion, race and sex impact vascular and central hemodynamic responses to exercise. Young AA and CA subjects exhibited differential responses in central stiffness and central BP after acute maximal exercise. Premenopausal women had greater augmented pressure at rest and after maximal aerobic exercise than men. Future research is needed to examine the potential mechanisms.

  8. Proximal Humerus

    NARCIS (Netherlands)

    Diercks, Ron L.; Bain, Gregory; Itoi, Eiji; Di Giacomo, Giovanni; Sugaya, Hiroyuki

    2015-01-01

    This chapter describes the bony structures of the proximal humerus. The proximal humerus is often regarded as consisting of four parts, which assists in understanding function and, more specially, describes the essential parts in reconstruction after fracture or in joint replacement. These are the

  9. The Effect Of Supraphysiologic Blood Pressure on Traumatic Brain Injury and Proximal Tissue Beds During Resuscitative Balloon Occlusion of the Aorta and Variable Aortic Control in a Porcine Model (Sus scrofa) of Polytrauma.

    Science.gov (United States)

    2017-04-27

    Control In A Porcine Model (Sus Scrofa) Of Polytrauma . PRINCIPAL INVESTIGATOR (PI) / TRAINING COORDINATOR (TC): Lt Col Timothy Williams DEPARTMENT...Mandatory) The Effect of REBOA, Partial Aortic Occlusion and Aggressive Blood Transfusion on Traumatic Brain Injury in a Swine Polytrauma Model

  10. Hypertrophic remodeling and increased arterial stiffness in patients with intracranial aneurysms.

    Science.gov (United States)

    Maltete, David; Bellien, Jeremy; Cabrejo, Lucie; Iacob, Michele; Proust, François; Mihout, Bruno; Thuillez, Christian; Guegan-Massardier, Evelyne; Joannides, Robinson

    2010-08-01

    Because an underlying arteriopathy might contribute to the development of intracranial aneurysms (IAs), we assessed the elastic properties of proximal conduit arteries in patients with IA. In 27 patients with previous ruptured IA and 27 control subjects matched for age, gender and BMI, we determined arterial pressure, internal diameter, intima-media thickness (IMT), circumferential wall stress (CWS) and elastic modulus (wall stiffness) in common carotid arteries using applanation tonometry and echotracking. Moreover, carotid augmentation index (AIx, arterial wave reflections) and carotid-to-femoral pulse wave velocity (PWV, aortic stiffness) were assessed. Compared with controls, patients with IA exhibited higher brachial and carotid systolic and diastolic blood pressures, with similar brachial but higher carotid artery pulse pressure (35 + or - 6mm Hg vs. 41 + or - 8mm Hg, P=0.014). Moreover, patients have higher PWV (7.8 + or - 1.2ms(-1) vs. 8.3 + or - 1.1ms(-1), P=0.048) and AIx (15.8 + or - 10.8% vs. 21.1 + or - 8.5%, PIA display a particular carotid artery phenotype with an exaggerated hypertrophic remodeling and altered elastic properties. Thus, a systemic arteriopathy might contribute, together with the arterial wall fatiguing effect of the increased pulsatile stress, to the pathogenesis of IA. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

  11. Transcatheter aortic valve replacement

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    ... gov/ency/article/007684.htm Transcatheter aortic valve replacement To use the sharing features on this page, please enable JavaScript. Transcatheter aortic valve replacement (TAVR) is surgery to replace the aortic valve. ...

  12. Augmented vascular smooth muscle cell stiffness and adhesion when hypertension is superimposed on aging.

    Science.gov (United States)

    Sehgel, Nancy L; Sun, Zhe; Hong, Zhongkui; Hunter, William C; Hill, Michael A; Vatner, Dorothy E; Vatner, Stephen F; Meininger, Gerald A

    2015-02-01

    Hypertension and aging are both recognized to increase aortic stiffness, but their interactions are not completely understood. Most previous studies have attributed increased aortic stiffness to changes in extracellular matrix proteins that alter the mechanical properties of the vascular wall. Alternatively, we hypothesized that a significant component of increased vascular stiffness in hypertension is due to changes in the mechanical and adhesive properties of vascular smooth muscle cells, and that aging would augment the contribution from vascular smooth muscle cells when compared with the extracellular matrix. Accordingly, we studied aortic stiffness in young (16-week-old) and old (64-week-old) spontaneously hypertensive rats and Wistar-Kyoto wild-type controls. Systolic and pulse pressures were significantly increased in young spontaneously hypertensive rats when compared with young Wistar-Kyoto rats, and these continued to rise in old spontaneously hypertensive rats when compared with age-matched controls. Excised aortic ring segments exhibited significantly greater elastic moduli in both young and old spontaneously hypertensive rats versus Wistar-Kyoto rats. were isolated from the thoracic aorta, and stiffness and adhesion to fibronectin were measured by atomic force microscopy. Hypertension increased both vascular smooth muscle cell stiffness and vascular smooth muscle cell adhesion, and these increases were both augmented with aging. By contrast, hypertension did not affect histological measures of aortic collagen and elastin, which were predominantly changed by aging. These findings support the concept that stiffness and adhesive properties of vascular smooth muscle cells are novel mechanisms contributing to the increased aortic stiffness occurring with hypertension superimposed on aging. © 2014 American Heart Association, Inc.

  13. Aortic stenosis: From diagnosis to optimal treatment

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    Tavčiovski Dragan

    2008-01-01

    Full Text Available Aortic stenosis is the most frequent valvular heart disease. Aortic sclerosis is the first characteristic lesion of the cusps, which is considered today as the process similar to atherosclerosis. Progression of the disease is an active process leading to forming of bone matrix and heavily calcified stiff cusps by inflammatory cells and osteopontin. It is a chronic, progressive disease which can remain asymptomatic for a long time even in the presence of severe aortic stenosis. Proper physical examination remains an essential diagnostic tool in aortic stenosis. Recognition of characteristic systolic murmur draws attention and guides further diagnosis in the right direction. Doppler echocardiography is an ideal tool to confirm diagnosis. It is well known that exercise tests help in stratification risk of asymptomatic aortic stenosis. Serial measurements of brain natriuretic peptide during a follow-up period may help to identify the optimal time for surgery. Heart catheterization is mostly restricted to preoperative evaluation of coronary arteries rather than to evaluation of the valve lesion itself. Currently, there is no ideal medical treatment for slowing down the disease progression. The first results about the effect of ACE inhibitors and statins in aortic sclerosis and stenosis are encouraging, but there is still not enough evidence. Onset symptoms based on current ACC/AHA/ESC recommendations are I class indication for aortic valve replacement. Aortic valve can be replaced with a biological or prosthetic valve. There is a possibility of percutaneous aortic valve implantation and transapical operation for patients that are contraindicated for standard cardiac surgery.

  14. Arterial stiffness assessment in patients with phenylketonuria

    Science.gov (United States)

    Hermida-Ameijeiras, Alvaro; Crujeiras, Vanesa; Roca, Iria; Calvo, Carlos; Leis, Rosaura; Couce, María-Luz

    2017-01-01

    Abstract In patients with phenylketonuria (PKU) compliant to diet greater tendency to overweight and higher inflammatory biomarkers levels than controls were reported. Although this could lead to atherogenesis, the elastic properties of large arteries in PKU patients have never been assessed. The aim of this study was to assess arterial stiffness measured by applanation tonometry in PKU patients compared to healthy controls. We carried out a cross-sectional study in 41 PKU patients (range age: 6–50 years old) and 41 age- and gender-matched healthy controls. Evaluated data included pharmacological treatment with sapropterin, clinical, and biochemical parameters. Aortic stiffness was assessed noninvasively by applanation tonometry measuring central blood pressure, aortic augmentation index (Aix@HR75), augmentation pressure (AP), and pulse wave velocity (PWV). We found higher PWV in classic PKU patients (6.60 m/second vs 5.26 m/second; P: .044). Percentage of PKU patients with PWV above 90 percentile was higher than controls (14.63% vs 2.32%; P: .048). A positive relationship was observed between the annual Phe median and PWV (r: 0.496; P: .012). PKU subjects with lower Phe tolerance showed more body weight (67.6 kg vs 56.8 kg; P: .012) and more PWV than those with higher Phe tolerance (6.55 m/second vs 5.42 m/second; P: .044). Our data show increased aortic stiffness in PKU patients, measured by applanation tonometry, when compared to healthy controls. Higher Phe levels are associated with a bigger PWV increase, which is not present in those subjects compliant to diet or under sapropterin treatment. These results could have marked effects in both research and clinical daily practice for a proper evaluation of cardiovascular risk in PKU subjects. PMID:29390507

  15. Evaluation of arterial stiffness in nondiabetic chronic kidney disease patients

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    Bodanapu Mastanvalli

    2017-01-01

    Full Text Available Chronic kidney disease (CKD is a growing problem worldwide. Clinical and epidemiologic studies have shown that structural and functional changes that occur in major arteries are a major contributing factor to the high mortality in uremic patients. Recent studies have shown a stepwise increase of the carotid-femoral pulse wave velocity (cfPWV from CKD Stage 1 to Stage 5. We evaluated the cfPWV and augmentation index (AIx, as indirect markers of arterial stiffness in patients with nondiabetic CKD and compared the values with normal population; we also evaluated the relationship between various stages of CKD and arterial stiffness markers. This cross-sectional study was carried out in the Department of Nephrology for a duration of two years from January 15, 2012, to January 14, 2014. Fifty patients with nondiabetic CKD were studied along with 50 healthy volunteers who did not have CKD, who served as controls. Assessment of arterial stiffness (blood pressure, PWV, heart rate, aortic augmentation pressure, and AIx was performed using the PeriScope device. PWV positively correlated with systolic and diastolic blood pressure, mean aortic arterial pressure, serum creatinine, and serum uric acid and negatively correlated with estimated glomerular filtration rate. Arterial stiffness increased as CKD stage increased and was higher in nondiabetic CKD group than in the general population. Arterial stiffness progressed gradually from CKD Stage 2 to 5, and then abruptly, in dialysis patients. Measures to decrease the arterial stiffness and its influence on decreasing cardiovascular events need further evaluation.

  16. Elevation of Matrix Metalloproteinases in Different Areas of Ascending Aortic Aneurysms in Patients with Bicuspid and Tricuspid Aortic Valves

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    Salah A. Mohamed

    2012-01-01

    Full Text Available Our aim is to investigate the elevation of matrix proteins in tissues obtained from distal, above the sinotubular junction (proximal, concave, and convex sites of aneurysms in the ascending aorta using a simultaneous multiplex protein detection system. Tissues were collected from 41 patients with ascending aortic aneurysms. A total of 31 patients had a bicuspid aortic valve (BAV, whereas 10 had a tricuspid aortic valve (TAV. Concave and convex aortic site samples were collected from all patients, whereas proximal and distal convexity samples were obtained from 19 patients with BAV and 7 patients with TAV. Simultaneous detection of matrix metalloproteinases (MMPs and their inhibitors (TIMPs was performed at each of the four aortic sites. MMP-2 levels were higher in the concave aortic sites than in the convex aortic sites. In contrast, MMP-8 levels were higher in the convex sites than in the concave sites, as were MMP-9 levels. In both BAV and TAV patients, TIMP-3 levels were higher in the concave sites than in the convex sites. However, TIMP-2 and TIMP-4 levels were significantly elevated in the sinotubular proximal aorta of BAV patients. Simultaneous detection of MMPs and TIMPs revealed different levels at different aortic sites in the same patient.

  17. Estimating Gear Teeth Stiffness

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2013-01-01

    The estimation of gear stiffness is important for determining the load distribution between the gear teeth when two sets of teeth are in contact. Two factors have a major influence on the stiffness; firstly the boundary condition through the gear rim size included in the stiffness calculation...... and secondly the size of the contact. In the FE calculation the true gear tooth root profile is applied. The meshing stiffness’s of gears are highly non-linear, it is however found that the stiffness of an individual tooth can be expressed in a linear form assuming that the contact length is constant....

  18. Aortic valve bypass

    DEFF Research Database (Denmark)

    Lund, Jens T; Jensen, Maiken Brit; Arendrup, Henrik

    2013-01-01

    In aortic valve bypass (AVB) a valve-containing conduit is connecting the apex of the left ventricle to the descending aorta. Candidates are patients with symptomatic aortic valve stenosis rejected for conventional aortic valve replacement (AVR) or transcatheter aortic valve implantation (TAVI). ...

  19. The conundrum of arterial stiffness, elevated blood pressure, and aging.

    Science.gov (United States)

    AlGhatrif, Majd; Lakatta, Edward G

    2015-02-01

    Isolated systolic hypertension is a major health burden that is expanding with the aging of our population. There is evidence that central arterial stiffness contributes to the rise in systolic blood pressure (SBP); at the same time, central arterial stiffening is accelerated in patients with increased SBP. This bidirectional relationship created a controversy in the field on whether arterial stiffness leads to hypertension or vice versa. Given the profound interdependency of arterial stiffness and blood pressure, this question seems intrinsically challenging, or probably naïve. The aorta's function of dampening the pulsatile flow generated by the left ventricle is optimal within a physiological range of distending pressure that secures the required distal flow, keeps the aorta in an optimal mechanical conformation, and minimizes cardiac work. This homeostasis is disturbed by age-associated, minute alterations in aortic hemodynamic and mechanical properties that induce short- and long-term alterations in each other. Hence, it is impossible to detect an "initial insult" at an epidemiological level. Earlier manifestations of these alterations are observed in young adulthood with a sharp decline in aortic strain and distensibility accompanied by an increase in diastolic blood pressure. Subsequently, aortic mechanical reserve is exhausted, and aortic remodeling with wall stiffening and dilatation ensue. These two phenomena affect pulse pressure in opposite directions and different magnitudes. With early remodeling, there is an increase in pulse pressure, due to the dominance of arterial wall stiffness, which in turn accelerates aortic wall stiffness and dilation. With advanced remodeling, which appears to be greater in men, the effect of diameter becomes more pronounced and partially offsets the effect of wall stiffness leading to plateauing in pulse pressure in men and slower increase in pulse pressure (PP) than that of wall stiffness in women. The complex nature of

  20. Critical appraisal of the differential effects of antihypertensive agents on arterial stiffness

    Directory of Open Access Journals (Sweden)

    Francesca Kum

    2010-06-01

    Full Text Available Francesca Kum, Janaka KarallieddeUnit for Metabolic Medicine, Cardiovascular Division, Kings College-Waterloo Campus, King’s College London, United KingdomAbstract: Increased central arterial stiffness, involving accelerated vascular ageing of the aorta, is a powerful and independent risk factor for early mortality and provides prognostic information above and beyond traditional risk factors for cardiovascular disease (CVD. Central arterial stiffness is an important determinant of pulse pressure; therefore, any pathological increase may result in left ventricular hypertrophy and impaired coronary perfusion. Central artery stiffness can be assessed noninvasively by measurement of aortic pulse wave velocity, which is the gold standard for measurement of arterial stiffness. Earlier, it was believed that changes in arterial stiffness, which are primarily influenced by long-term pressure-dependent structural changes, may be slowed but not reversed by pharmacotherapy. Recent studies with drugs that inhibit the renin–angiotensin–aldosterone system, advanced glycation end products crosslink breakers, and endothelin antagonists suggest that blood pressure (BP-independent reduction and reversal of arterial stiffness are feasible. We review the recent literature on the differential effect of antihypertensive agents either as monotherapy or combination therapy on arterial stiffness. Arterial stiffness is an emerging therapeutic target for CVD risk reduction; however, further clinical trials are required to confirm whether BP-independent changes in arterial stiffness directly translate to a reduction in CVD events.Keywords: aortic pulse wave velocity, augmentation index, blood pressure, renin–angiotensin–aldosterone system

  1. Abdominal Aortic Dissection with Acute Mesenteric Ischemia in a Patient with Marfan Syndrome

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    Chii-Shyan Lay

    2006-07-01

    Full Text Available Marfan syndrome is an autosomal dominant inherited disorder of connective tissue, with various complications manifested primarily in the cardiovascular system. It potentially leads to aortic dissection and rupture, these being the major causes of death. We report a patient who complained of acute abdominal pain, which presented as acute mesenteric ischemia combined with abdominal aortic dissection. Echocardiography showed enlargement of the aortic root and mitral valve prolapse. Abdominal computed tomography scan revealed acute mesenteric ischemia due to abdominal aortic dissection. Finally, the patient underwent surgery of aortic root replacement and had a successful outcome. Therefore, we suggest that for optimal risk assessment and monitoring of patients with Marfan syndrome, both aortic stiffness and the diameter of the superior mesenteric vein compared with that of the superior mesenteric artery are useful screening methods to detect acute mesenteric ischemia secondary to abdominal aortic dissection. Early diagnosis and early treatment can decrease the high mortality rate of patients with Marfan syndrome.

  2. Selective Aortic Arch and Root Replacement in Repair of Acute Type A Aortic Dissection.

    Science.gov (United States)

    Fleischman, Fernando; Elsayed, Ramsey S; Cohen, Robbin G; Tatum, James M; Kumar, S Ram; Kazerouni, Kayvan; Mack, Wendy J; Barr, Mark L; Cunningham, Mark J; Hackmann, Amy E; Baker, Craig J; Starnes, Vaughn A; Bowdish, Michael E

    2018-02-01

    Controversy exists regarding the optimal extent of repair for type A aortic dissection. Our approach is to replace the ascending aorta, and only replace the aortic root or arch when intimal tears are present in those areas. We examined intermediate outcomes with this approach to acute type A aortic dissection repair. Between March 2005 and October 2016, 195 patients underwent repair of acute type A aortic dissection. Repair was categorized by site of proximal and distal anastomosis and extent of repair. Mean follow-up was 31.0 ± 30.9 months. Kaplan-Meier analysis was used to assess survival. Multiple variable Cox proportional hazards modeling was utilized to identify factors associated with overall mortality. Overall survival was 85.1%, 83.9%, 79.1%, and 74.4% at 6, 12, 36, and 60 months, respectively. Eight patients required reintervention. The cumulative incidence of aortic reintervention at 1 year with death as a competing outcome was 3.95%. Multiple variable regression analysis identified factors such as age, preoperative renal failure, concomitant thoracic endograft, postoperative myocardial infarction and sepsis, and need for extracorporeal membrane oxygenation as predictive of overall mortality. Neither proximal or distal extent of repair, nor need for reintervention affected overall survival (proximal: hazard ratio 1.63, 95% confidence interval: 0.75 to 3.51, p = 0.22; distal: hazard ratio 1.12, 95% confidence interval: 0.43 to 2.97, p = 0.81; reintervention: hazard ratio 0.03, 95% confidence interval: 0.002 to 0.490, p < 0.01). A selective approach to root and arch repair in acute type A aortic dissection is safe. If aortic reintervention is needed, survival does not appear to be affected. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  3. The risk for type B aortic dissection in Marfan syndrome.

    Science.gov (United States)

    den Hartog, Alexander W; Franken, Romy; Zwinderman, Aeilko H; Timmermans, Janneke; Scholte, Arthur J; van den Berg, Maarten P; de Waard, Vivian; Pals, Gerard; Mulder, Barbara J M; Groenink, Maarten

    2015-01-27

    Aortic dissections involving the descending aorta are a major clinical problem in patients with Marfan syndrome. The purpose of this study was to identify clinical parameters associated with type B aortic dissection and to develop a risk model to predict type B aortic dissection in patients with Marfan syndrome. Patients with the diagnosis of Marfan syndrome and magnetic resonance imaging or computed tomographic imaging of the aorta were followed for a median of 6 years for the occurrence of type B dissection or the combined end point of type B aortic dissection, distal aortic surgery, and death. A model using various clinical parameters as well as genotyping was developed to predict the risk for type B dissection in patients with Marfan syndrome. Between 1998 and 2013, 54 type B aortic dissections occurred in 600 patients with Marfan syndrome (mean age 36 ± 14 years, 52% male). Independent variables associated with type B aortic dissection were prior prophylactic aortic surgery (hazard ratio: 2.1; 95% confidence interval: 1.2 to 3.8; p = 0.010) and a proximal descending aorta diameter ≥27 mm (hazard ratio: 2.2; 95% confidence interval: 1.1 to 4.3; p = 0.020). In the risk model, the 10-year occurrence of type B aortic dissection in low-, moderate-, and high-risk patients was 6%, 19%, and 34%, respectively. Angiotensin II receptor blocker therapy was associated with fewer type B aortic dissections (hazard ratio: 0.3; 95% confidence interval: 0.1 to 0.9; p = 0.030). Patients with Marfan syndrome with prior prophylactic aortic surgery are at substantial risk for type B aortic dissection, even when the descending aorta is only slightly dilated. Angiotensin II receptor blocker therapy may be protective in the prevention of type B aortic dissections. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  4. Effects of Ramadan fasting on body composition and arterial stiffness.

    Science.gov (United States)

    Sezen, Yusuf; Altiparmak, Ibrahim Halil; Erkus, Muslihittin Emre; Kocarslan, Aydemir; Kaya, Zekeriya; Gunebakmaz, Ozgur; Demirbag, Recep

    2016-12-01

    To examine the effects of Ramadan fasting on body composition, arterial stiffness and resting heart rate. This prospective study was conducted at the Department of Cardiology, Harran University, Sanliurfa, Turkey, during Ramadan 2015, and comprised overweight and obese males. Body composition, arterial stiffness and echocardiography were assessed before and after Ramadan. Body composition was assessed by bioelectrical impedance analysis using segmental body composition analyser. Arterial stiffness and haemodynamic parameters were also measured. SPSS 20 was used for data analysis. Of the 100 subjects enrolled, 70(70%) were included. The overall mean age was 37±7 years. No significant changes were observed in blood pressures, resting heart rate, aortic pulse wave velocity, aortic augmentation index-75, aortic pulse pressure, brachial pulse pressure, basal metabolic rate, total body water, fat-free mass, and echocardiographic parameters (p>0.05 each). Although aortic pulse wave velocity (m/s) and augmentation index-75 (%) decreased after fasting period compared to that of before Ramadan, these reductions did not reach statistically significant levels (8.6±1.8 vs. 8.9±1.9, and 13.6±6.6 vs. 14.7±9.3, respectively; p>0.05 each). Body mass index, waist-hip ratio, body water rate, percentage of body fat mass, body fat mass, and visceral fat mass percentage were significantly reduced (pRamadan. Ramadan fasting had beneficial effects on body composition, but did not have any significant effect on arterial stiffness and resting heart rate.

  5. Posttraumatic stiff elbow

    Directory of Open Access Journals (Sweden)

    Ravi Mittal

    2017-01-01

    Full Text Available Posttraumatic stiff elbow is a frequent and disabling complication and poses serious challenges for its management. In this review forty studies were included to know about the magnitude of the problem, causes, pathology, prevention, and treatment of posttraumatic stiff elbow. These studies show that simple measures such as internal fixation, immobilization in extension, and early motion of elbow joint are the most important steps that can prevent elbow stiffness. It also supports conservative treatment in selected cases. There are no clear guidelines about the choice between the numerous procedures described in literature. However, this review article disproves two major beliefs-heterotopic ossification is a bad prognostic feature, and passive mobilization of elbow causes elbow stiffness.

  6. Aortic Annular Enlargement during Aortic Valve Replacement

    Directory of Open Access Journals (Sweden)

    Selman Dumani

    2016-09-01

    Full Text Available In the surgery of aortic valve replacement is always attempted, as much as possible, to implant the larger prosthesis with the mains goals to enhance the potential benefits, to minimise transvalvular gradient, decrease left ventricular size and avoid the phenomenon of patient-prosthesis mismatch. Implantation of an ideal prosthesis often it is not possible, due to a small aortic annulus. A variety of aortic annulus enlargement techniques is reported to avoid patient-prosthesis mismatch. We present the case that has submitted four three times open heart surgery. We used Manouguian technique to enlarge aortic anulus with excellent results during the fourth time of surgery.

  7. Central Hemodynamics and Arterial Stiffness in Systemic Sclerosis.

    Science.gov (United States)

    Bartoloni, Elena; Pucci, Giacomo; Cannarile, Francesca; Battista, Francesca; Alunno, Alessia; Giuliani, Marco; Cafaro, Giacomo; Gerli, Roberto; Schillaci, Giuseppe

    2016-12-01

    Although microvascular disease is a hallmark of systemic sclerosis (SSc), a higher prevalence of macrovascular disease and a poorer related prognosis have been reported in SSc than in the general population. The simultaneous assessment of prognostically relevant functional properties of larger and smaller arteries, and their effects on central hemodynamics, has never been performed in SSc using the state-of-the-art techniques. Thirty-four women with SSc (aged 61±15 years, disease duration 17±12 years, and blood pressure 123/70±18/11 mm Hg) and 34 healthy women individually matched by age and mean arterial pressure underwent the determination of carotid-femoral (aortic) and carotid-radial (upper limb) pulse wave velocity (a direct measure of arterial stiffness), aortic augmentation (a measure of the contribution of reflected wave to central pulse pressure), and aortobrachial pulse pressure amplification (brachial/aortic pulse pressure) through applanation tonometry (SphygmoCor). Patients and controls did not differ by carotid-femoral or carotid-radial pulse wave velocity. Aortic augmentation index corrected for a heart rate of 75 bpm (AIx@75) was higher in women with SSc (30.9±16% versus 22.2±12%; P=0.012). Patients also had a lower aortobrachial amplification of pulse pressure (1.22±0.18 versus 1.33±0.25; P=0.041). SSc was an independent predictor of AIx@75 (direct) and pulse pressure amplification (inverse). Among patients, age, mean arterial pressure, and C-reactive protein independently predicted carotid-femoral pulse wave velocity. Age and mean arterial pressure were the only predictors of AIx@75. Women with SSc have increased aortic augmentation and decreased pulse pressure amplification (both measures of the contribution of reflected wave to central waveform) but no changes in aortic or upper limb arterial stiffness. Microvascular involvement occurs earlier than large artery stiffening in SSc. © 2016 American Heart Association, Inc.

  8. Altered Aortic Upper Wall TDI Velocity Is Inversely Related with Left Ventricular Diastolic Function in Operated Tetralogy of Fallot.

    Science.gov (United States)

    Bassareo, Pier Paolo; Saba, Luca; Marras, Andrea R; Mercuro, Giuseppe

    2016-12-01

    Postoperative tetralogy of Fallot (TOF) patients often develop progressive aortic root dilatation due to an impairment in aortic elastic properties. (1) to assess aortic elasticity at the level of the aortic upper wall by tissue Doppler imaging (TDI); (2) to evaluate the influence of aortic elasticity on left ventricular (LV) diastolic function in TOF patients. Twenty-eight postoperative TOF patients (14 males, 14 females. Mean age: 25.7 ± 1.6 years) and 28 age- and sex-matched normal subjects were examined. Aortic distensibility and stiffness index were calculated. Aortic wall systolic and diastolic velocities, LV systolic and diastolic parameters were assessed by TDI. Aortic distensibility was significantly lower (P = .024), and aortic stiffness index significantly higher (P = .036) in TOF patients compared to controls. E/E' was significantly higher in TOF than in control group (P < .001). Aortic upper wall early diastolic velocity (AWEDV) was significantly correlated with aortic stiffness index (r: -0.42; P < .03), aortic distensibility (r = 0.54; P < .004), left atrial volume (r = -0.62; P = .0004), and E/E' ratio (r = -0.87; P < .0001). The latter relationship remained significant even when excluding the influence of age at surgery (r = -0.60; P < .0007) and of previous palliative surgery (r = -0.53; P < .02). Aortic elastic properties can be directly assessed using TDI to measure AWEDV. Aortic elasticity is significantly lower in postoperative TOF patients, exerting a negative effect also on LV diastolic function, with a potential long-term influence on clinical status. © 2016 Wiley Periodicals, Inc.

  9. Aortic valve surgery - open

    Science.gov (United States)

    ... gov/ency/article/007408.htm Aortic valve surgery - open To use the sharing features on this page, ... separates the heart and aorta. The aortic valve opens so blood can flow out. It then closes ...

  10. Abdominal Aortic Aneurysm (AAA)

    Science.gov (United States)

    ... Professions Site Index A-Z Abdominal Aortic Aneurysm (AAA) Abdominal aortic aneurysm (AAA) occurs when atherosclerosis or plaque buildup causes the ... weak and bulge outward like a balloon. An AAA develops slowly over time and has few noticeable ...

  11. Locally Different Endothelial Nitric Oxide Synthase Protein Levels in Ascending Aortic Aneurysms of Bicuspid and Tricuspid Aortic Valve

    Directory of Open Access Journals (Sweden)

    Salah A. Mohamed

    2012-01-01

    Full Text Available Aims. Dysregulated expression of the endothelial nitric oxide synthase (eNOS is observed in aortic aneurysms associated with bicuspid aortic valve (BAV. We determined eNOS protein levels in various areas in ascending aortic aneurysms. Methods and Results. Aneurysmal specimens were collected from 19 patients, 14 with BAV and 5 with tricuspid aortic valve (TAV. ENOS protein levels were measured in the outer curve (convexity, the opposite side (concavity, the distal and above the sinotubular junction (proximal aneurysm. Cultured aortic cells were treated with NO synthesis inhibitor L-NAME and the amounts of 35 apoptosis-related proteins were determined. In patients with BAV, eNOS levels were significantly lower in the proximal aorta than in the concavity and distal aorta. ENOS protein levels were also lower in the convexity than in the concavity. While the convexity and distal aorta showed similar eNOS protein levels in BAV and TAV patients, levels were higher in TAV proximal aorta. Inhibition of NO synthesis in aneurysmal aortic cells by L-NAME led to a cytosolic increase in the levels of mitochondrial serine protease HTRA2/Omi. Conclusion. ENOS protein levels were varied at different areas of the aneurysmal aorta. The dysregulation of nitric oxide can lead to an increase in proapoptotic HTRA2/Omi.

  12. Aortic Arch Aneurysms: Treatment with Extra anatomical Bypass and Endovascular Stent-Grafting

    International Nuclear Information System (INIS)

    Kato, Noriyuki; Shimono, Takatsugu; Hirano, Tadanori; Mizumoto, Toru; Ishida, Masaki; Fujii, Hideki; Yada, Isao; Takeda, Kan

    2002-01-01

    Endovascular repair of thoracic aortic aneurysms is emerging as an attractive alternative to surgical graft replacement. However,patients with aortic arch aneurysms are often excluded from the target of endovascular repair because of lack of suitable landing zones, especially at the proximal ones. In this paper we describe our method for treating patients with aortic arch aneurysms using a combination of extra anatomical bypass surgery and endovascular stent-grafting

  13. Nondiabetic Glucometabolic Status and Progression of Aortic Stiffness

    DEFF Research Database (Denmark)

    McEniery, Carmel M; Wilkinson, Ian B; Johansen, Nanna B

    2017-01-01

    -up. At baseline, cfPWV was associated with fasting and 2-h postload glucose, HbA1c, and HOMA-insulin resistance (HOMA-IR). HbA1c and HOMA-IR were associated with progression of cfPWV after adjusting for physiological confounders and cardiovascular risk factors. A 1 SD higher HbA1c and HOMA-IR were associated...... with greater increases in cfPWV (0.11 m/s per 5 years [95% CI 0.04, 0.18], P = 0.003 and 0.09 m/s per 5 years [0.01, 0.17], P = 0.03, respectively). Additional adjustment for BMI weakened the association with HOMA-IR but not with HbA1c. CONCLUSIONS HbA1c is independently associated with accelerated progression...

  14. Uric acid promotes vascular stiffness, maladaptive inflammatory responses and proteinuria in western diet fed mice.

    Science.gov (United States)

    Aroor, Annayya R; Jia, Guanghong; Habibi, Javad; Sun, Zhe; Ramirez-Perez, Francisco I; Brady, Barron; Chen, Dongqing; Martinez-Lemus, Luis A; Manrique, Camila; Nistala, Ravi; Whaley-Connell, Adam T; Demarco, Vincent G; Meininger, Gerald A; Sowers, James R

    2017-09-01

    Aortic vascular stiffness has been implicated in the development of cardiovascular disease (CVD) and chronic kidney disease (CKD) in obese individuals. However, the mechanism promoting these adverse effects are unclear. In this context, promotion of obesity through consumption of a western diet (WD) high in fat and fructose leads to excess circulating uric acid. There is accumulating data implicating elevated uric acid in the promotion of CVD and CKD. Accordingly, we hypothesized that xanthine oxidase(XO) inhibition with allopurinol would prevent a rise in vascular stiffness and proteinuria in a translationally relevant model of WD-induced obesity. Four-week-old C57BL6/J male mice were fed a WD with excess fat (46%) and fructose (17.5%) with or without allopurinol (125mg/L in drinking water) for 16weeks. Aortic endothelial and extracellular matrix/vascular smooth muscle stiffness was evaluated by atomic force microscopy. Aortic XO activity, 3-nitrotyrosine (3-NT) and aortic endothelial sodium channel (EnNaC) expression were evaluated along with aortic expression of inflammatory markers. In the kidney, expression of toll like receptor 4 (TLR4) and fibronectin were assessed along with evaluation of proteinuria. XO inhibition significantly attenuated WD-induced increases in plasma uric acid, vascular XO activity and oxidative stress, in concert with reductions in proteinuria. Further, XO inhibition prevented WD-induced increases in aortic EnNaC expression and associated endothelial and subendothelial stiffness. XO inhibition also reduced vascular pro-inflammatory and maladaptive immune responses induced by consumption of a WD. XO inhibition also decreased WD-induced increases in renal TLR4 and fibronectin that associated proteinuria. Consumption of a WD leads to elevations in plasma uric acid, increased vascular XO activity, oxidative stress, vascular stiffness, and proteinuria all of which are attenuated with allopurinol administration. Copyright © 2017 Elsevier Inc

  15. Atheroembolization and potential air embolization during aortic declamping in open repair of a pararenal aortic aneurysm: A case report.

    Science.gov (United States)

    Dregelid, Einar Børre; Lilleng, Peer Kåre

    2016-01-01

    When ischemic events ascribable to microembolization occur during open repair of proximal abdominal aortic aneurysms, a likely origin of atheroembolism is not always found. A 78-year old man with enlargement of the entire aorta underwent open repair for a pararenal abdominal aortic aneurysm using supraceliac aortic clamping for 20min. Then the graft was clamped, the supraceliac clamp was removed, and the distal and right renal anastomoses were also completed. The patient was stable throughout the operation with only transient drop in blood pressure on reperfusion. Postoperatively the patient developed ischemia, attributable to microembolization, in legs, small intestine, gall bladder and kidneys. He underwent fasciotomy, small bowel and gall bladder resections. Intestinal absorptive function did not recover adequately and he died after 4 months. Microscopic examination of hundreds of intestinal, juxtaintestinal mesenteric, and gall bladder arteries showed a few ones containing cholesterol emboli. It is unsure whether a few occluded small arteries out of several hundred could have caused the ischemic injury alone. There had been only moderate backbleeding from aortic branches above the proximal anastomosis while it was sutured. Inadvertently, remaining air in the graft, aorta, and aortic branches may have been whipped into the pulsating blood, resulting in air microbubbles, when the aortic clamp was removed. Although both atheromatous particles and air microbubbles are well-known causes of iatrogenic microembolization, the importance of air microembolization in open repair of pararenal aortic aneurysms is not known and need to be studied. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  16. Stiff-Person Syndrome and Graves’ Disease

    Directory of Open Access Journals (Sweden)

    Lais Moreira Medeiros MD

    2016-12-01

    Full Text Available A 9-year-old female child presented with a history of falls, weight loss, diffuse leg pain, and progressive gait disorder, following 1 previous event described as a tonic–clonic seizure. She had increased thyroid volume, brisk symmetric reflexes, abnormal gait, and painful spasms of the paraspinal musculature. Thyroid function tests indicated biochemical hyperthyroidism, and thyrotropin receptor antibodies were positive. Her electromyography showed continuous activation of normal motor units of the paraspinal and proximal lower extremity muscles. The patient had a diagnosis of Graves’ disease with associated stiff-person syndrome, with elevated anti–glutamic acid decarboxylase antibody levels. After intravenous immunoglobulin therapy, her ambulation was substantially improved and the symptoms of stiff-person syndrome decreased dramatically.

  17. Acute aortic syndromes: definition, prognosis and treatment options.

    Science.gov (United States)

    Carpenter, S W; Kodolitsch, Y V; Debus, E S; Wipper, S; Tsilimparis, N; Larena-Avellaneda, A; Diener, H; Kölbel, T

    2014-04-01

    Acute aortic syndromes (AAS) are life-threatening vascular conditions of the thoracic aorta presenting with acute pain as the leading symptom in most cases. The incidence is approximately 3-5/100,000 in western countries with increase during the past decades. Clinical suspicion for AAS requires immediate confirmation with advanced imaging modalities. Initial management of AAS addresses avoidance of progression by immediate medical therapy to reduce aortic shear stress. Proximal symptomatic lesions with involvement of the ascending aorta are surgically treated in the acute setting, whereas acute uncomplicated distal dissection should be treated by medical therapy in the acute period, followed by surveillance and repeated imaging studies. Acute complicated distal dissection requires urgent invasive treatment and thoracic endovascular aortic repair has become the treatment modality of choice because of favorable outcomes compared to open surgical repair. Intramural hematoma, penetrating aortic ulcers, and traumatic aortic injuries of the descending aorta harbor specific challenges compared to aortic dissection and treatment strategies are not as uniformly defined as in aortic dissection. Moreover these lesions have a different prognosis. Once the acute period of aortic syndrome has been survived, a lifelong medical treatment and close surveillance with repeated imaging studies is essential to detect impending complications which might need invasive treatment within the short-, mid- or long-term.

  18. Arterial stiffness, pressure and flow pulsatility and brain structure and function: the Age, Gene/Environment Susceptibility--Reykjavik study.

    Science.gov (United States)

    Mitchell, Gary F; van Buchem, Mark A; Sigurdsson, Sigurdur; Gotal, John D; Jonsdottir, Maria K; Kjartansson, Ólafur; Garcia, Melissa; Aspelund, Thor; Harris, Tamara B; Gudnason, Vilmundur; Launer, Lenore J

    2011-11-01

    Aortic stiffness increases with age and vascular risk factor exposure and is associated with increased risk for structural and functional abnormalities in the brain. High ambient flow and low impedance are thought to sensitize the cerebral microcirculation to harmful effects of excessive pressure and flow pulsatility. However, haemodynamic mechanisms contributing to structural brain lesions and cognitive impairment in the presence of high aortic stiffness remain unclear. We hypothesized that disproportionate stiffening of the proximal aorta as compared with the carotid arteries reduces wave reflection at this important interface and thereby facilitates transmission of excessive pulsatile energy into the cerebral microcirculation, leading to microvascular damage and impaired function. To assess this hypothesis, we evaluated carotid pressure and flow, carotid-femoral pulse wave velocity, brain magnetic resonance images and cognitive scores in participants in the community-based Age, Gene/Environment Susceptibility--Reykjavik study who had no history of stroke, transient ischaemic attack or dementia (n = 668, 378 females, 69-93 years of age). Aortic characteristic impedance was assessed in a random subset (n = 422) and the reflection coefficient at the aorta-carotid interface was computed. Carotid flow pulsatility index was negatively related to the aorta-carotid reflection coefficient (R = -0.66, Pwave velocity were each associated with increased risk for silent subcortical infarcts (hazard ratios of 1.62-1.71 per standard deviation, Pwave velocity was associated with higher white matter hyperintensity volume (0.108 ± 0.045 SD/SD, P = 0.018). Pulsatility index was associated with lower whole brain (-0.127 ± 0.037 SD/SD, Pwave velocity (-0.095 ± 0.043 SD/SD, P = 0.028) and carotid pulse pressure (-0.114 ± 0.045 SD/SD, P = 0.013) were associated with lower memory scores. Pulsatility index was associated with lower memory scores (-0.165 ± 0.039 SD/SD, Pwave

  19. Metabolomic profiles of lipid metabolism, arterial stiffness and hemodynamics in male coronary artery disease patients

    Directory of Open Access Journals (Sweden)

    Kaido Paapstel

    2016-06-01

    Conclusions: We demonstrated an independent association between the serum medium- and long-chain acylcarnitine profile and aortic stiffness for the CAD patients. In addition to the lipid-related classical CVD risk markers, the intermediates of lipid metabolism may serve as novel indicators for altered vascular function.

  20. Stiff quantum polymers

    OpenAIRE

    Kleinert, H.

    2009-01-01

    At ultralow temperatures, polymers exhibit quantum behavior, which is calculated here for the second and fourth moments of the end-to-end distribution in the large-stiffness regime. The result should be measurable for polymers in wide optical traps.

  1. Transesophageal echocardiographic strain imaging predicts aortic biomechanics: Beyond diameter.

    Science.gov (United States)

    Emmott, Alexander; Alzahrani, Haitham; Alreishidan, Mohammed; Therrien, Judith; Leask, Richard L; Lachapelle, Kevin

    2018-03-11

    Clinical guidelines recommend resection of ascending aortic aneurysms at diameters 5.5 cm or greater to prevent rupture or dissection. However, approximately 40% of all ascending aortic dissections occur below this threshold. We propose new transesophageal echocardiography strain-imaging moduli coupled with blood pressure measurements to predict aortic dysfunction below the surgical threshold. A total of 21 patients undergoing aortic resection were recruited to participate in this study. Transesophageal echocardiography imaging of the aortic short-axis and invasive radial blood pressure traces were taken for 3 cardiac cycles. By using EchoPAC (GE Healthcare, Madison, Wis) and postprocessing in MATLAB (MathWorks, Natick, Mass), circumferential stretch profiles were generated and combined with the blood pressure traces. From these data, 2 in vivo stiffness moduli were calculated: the Cardiac Cycle Pressure Modulus and Cardiac Cycle Stress Modulus. From the resected aortic ring, testing squares were isolated for ex vivo mechanical analysis and histopathology. Each square underwent equibiaxial tensile testing to generate stress-stretch profiles for each patient. Two ex vivo indices were calculated from these profiles (energy loss and incremental stiffness) for comparison with the Cardiac Cycle Pressure Modulus and Cardiac Cycle Stress Modulus. The echo-derived stiffness moduli demonstrate positive significant covariance with ex vivo tensile biomechanical indices: energy loss (vs Cardiac Cycle Pressure Modulus: R 2  = 0.5873, P biomechanics and histopathology, which demonstrates the added benefit of using simple echocardiography-derived biomechanics to stratify patient populations. Copyright © 2018. Published by Elsevier Inc.

  2. Relationship between Static Stiffness and Modal Stiffness of Structures

    Directory of Open Access Journals (Sweden)

    Tianjian Ji Tianjian Ji

    2010-02-01

    Full Text Available This paper derives the relationship between the static stiffness and modal stiffness of a structure. The static stiffness and modal stiffness are two important concepts in both structural statics and dynamics. Although both stiffnesses indicate the capacity of the structure to resist deformation, they are obtained using different methods. The former is calculated by solving the equations of equilibrium and the latter can be obtained by solving an eigenvalue problem. A mathematical relationship between the two stiffnesses was derived based on the definitions of two stiffnesses. This relationship was applicable to a linear system and the derivation of relationships does not reveal any other limitations. Verification of the relationship was given by using several examples. The relationship between the two stiffnesses demonstrated that the modal stiffness of the fundamental mode was always larger than the static stiffness of a structure if the critical point and the maximum mode value are at the same node, i.e. for simply supported beam and seven storeys building are 1.5% and 15% respectively. The relationship could be applied into real structures, where the greater the number of modes being considered, the smaller the difference between the modal stiffness and the static stiffness of a structure.

  3. Abdominal aortic aneurysm neck remodeling after Anaconda stent graft implantation.

    Science.gov (United States)

    Vukovic, Elisabeth; Czerny, Martin; Beyersdorf, Friedhelm; Wolkewitz, Martin; Berezowski, Mikolaj; Siepe, Matthias; Blanke, Philipp; Rylski, Bartosz

    2018-05-24

    The aim of this study was to define how the proximal landing zone changes geometrically after endovascular abdominal aortic aneurysm repair (EVAR) with the Anaconda (Vascutek, Inchinnan, United Kingdom) stent graft. Among 230 patients who underwent Anaconda stent graft implantation between 2005 and 2014, we included 126 with adequate computed tomography (CT) image quality and follow-up. CT analysis entailed the geometric changes in the main body, proximal rings, and proximal landing zone. The median CT follow-up was 2.0 years (345.8 patients-years). The proximal portion of the main body ring system flattened within the first year after EVAR, resulting in an up to 30° increase in the upper ring's angle in 40% patients and up to 40° increase in 24% patients. One year after EVAR, the upper ring angle increase slowed down. Aortic diameter measured at the level of the upper and lower ring expanded by 2 to 4 mm within 1 year, but remained unchanged afterward. The main body migrated continuously down toward the aortic bifurcation, attaining an average 6-mm increase in the distance between the superior mesenteric artery and main body within 4 years. Freedom from endoleak type IA was 95 ± 2% and 93 ± 3% after 1 and 4 years, respectively. The Anaconda main body ring system in its proximal portion flattens within the first year after EVAR, leading to an increase of 2 to 4 mm in the proximal landing zone's aortic diameter. The main body migrates slowly but continuously down toward the aortic bifurcation. Copyright © 2018 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  4. On gear tooth stiffness evaluation

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard; Jørgensen, Martin Felix

    2014-01-01

    The estimation of gear stiffness is important for determining the load distribution between the gear teeth when two sets of teeth are in contact. Two factors have a major influence on the stiffness; firstly the boundary condition through the gear rim size included in the stiffness calculation...

  5. Endovascular Aortic Aneurysm Repair with Chimney and Snorkel Grafts: Indications, Techniques and Results

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Rakesh P., E-mail: rpatel9@nhs.net [Northwick Park Hospital, Department of Vascular Radiology (United Kingdom); Katsargyris, Athanasios, E-mail: kthanassos@yahoo.com; Verhoeven, Eric L. G., E-mail: Eric.Verhoeven@klinikum-nuernberg.de [Klinikum Nuernberg, Department of Vascular and Endovascular Surgery (Germany); Adam, Donald J., E-mail: donald.adam@tiscali.co.uk [Heartlands Hospital, Department of Vascular Surgery (United Kingdom); Hardman, John A., E-mail: johnhardman@doctors.org.uk [Royal United Hospital Bath, Department of Vascular Radiology (United Kingdom)

    2013-12-15

    The chimney technique in endovascular aortic aneurysm repair (Ch-EVAR) involves placement of a stent or stent-graft parallel to the main aortic stent-graft to extend the proximal or distal sealing zone while maintaining side branch patency. Ch-EVAR can facilitate endovascular repair of juxtarenal and aortic arch pathology using available standard aortic stent-grafts, therefore, eliminating the manufacturing delays required for customised fenestrated and branched stent-grafts. Several case series have demonstrated the feasibility of Ch-EVAR both in acute and elective cases with good early results. This review discusses indications, technique, and the current available clinical data on Ch-EVAR.

  6. A proposal for standardizing computed tomography reports on abdominal aortic aneurysms

    International Nuclear Information System (INIS)

    Torlai, Fabiola Goda; Meirelles, Gustavo S. Portes; Miranda Junior, Fausto; Fonseca, Jose Honorio A.P. da; Ajzen, Sergio; D'Ippolito, Giuseppe

    2006-01-01

    Objective: to propose a model to standardize computed tomography reports on abdominal aortic aneurysms. Materials and methods: interviews were carried out with members of the Vascular Surgery Division of our institution, in the period between April and October 2004, aiming at developing a standardized model of computed tomography reports on abdominal aortic aneurysms. Based on this model, a questionnaire was elaborated and sent to other nine surgeons, all of them experienced in the field of abdominal aortic surgery. The questionnaires response rate was 55.5% (5/9). Results: the most frequently mentioned parameters of interest for evaluation of abdominal aortic aneurysms were: maximum diameter of proximal aortic neck, proximal aortic neck length to lower renal arteries, shape of proximal aortic neck, maximum diameter of the aneurysm and diameter of the common iliac arteries. These data allowed the development of a proposal for a model to standardize computed tomography reports. Conclusion: a model for standardized tomographic analysis of abdominal aortic aneurysms has met vascular surgeons' needs for following-up patients and planning their treatment. (author)

  7. Photoplethysmographic signal waveform index for detection of increased arterial stiffness

    International Nuclear Information System (INIS)

    Pilt, K; Meigas, K; Ferenets, R; Temitski, K; Viigimaa, M

    2014-01-01

    The aim of this research was to assess the validity of the photoplethysmographic (PPG) waveform index PPGAI for the estimation of increased arterial stiffness. For this purpose, PPG signals were recorded from 24 healthy subjects and from 20 type II diabetes patients. The recorded PPG signals were processed with the analysis algorithm developed and the waveform index PPGAI similar to the augmentation index (AIx) was calculated. As a reference, the aortic AIx was assessed and normalized for a heart rate of 75 bpm (AIx@75) by a SphygmoCor device. A strong correlation (r = 0.85) between the PPGAI and the aortic AIx@75 and a positive correlation of both indices with age were found. Age corrections for the indices PPGAI and AIx@75 as regression models from the signals of healthy subjects were constructed. Both indices revealed a significant difference between the groups of diabetes patients and healthy controls. However, the PPGAI provided the best statistical discrimination for the group of subjects with increased arterial stiffness. The waveform index PPGAI based on the inexpensive PPG technology can be considered as a perspective measure of increased arterial stiffness estimation in clinical screenings. (paper)

  8. Low rate of reoperations after acute type A aortic dissection repair from The Nordic Consortium Registry

    DEFF Research Database (Denmark)

    Pan, Emily; Gudbjartsson, Tomas; Ahlsson, Anders

    2018-01-01

    Bakey classification nor the extent of proximal or distal repair predicted freedom from a later reoperation. The only independent risk factor associated with a later proximal reoperation was a history of connective tissue disease. CONCLUSIONS: Type A aortic dissection repair in low- to medium-volume centers......OBJECTIVES: To describe the relationship between the extent of primary aortic repair and the incidence of reoperations after surgery for type A aortic dissection. METHODS: A retrospective cohort of 1159 patients treated for type A aortic dissection at eight Nordic low- to medium......-sized cardiothoracic centers from 2005 to 2014. Data were gathered from patient records and national registries. Patients were separately divided into 3 groups according to the distal anastomoses technique (ascending aorta [n = 791], hemiarch [n = 247], and total arch [n = 66]), and into 2 groups for proximal repair...

  9. When operable patients become inoperable: conversion of a surgical aortic valve replacement into transcatheter aortic valve implantation

    DEFF Research Database (Denmark)

    Olsen, Lene Kjaer; Arendrup, Henrik; Engstrøm, Thomas

    2009-01-01

    . On extracorporal circulation it was reconized that the aortic annulus, the coronary ostiae and the proximal part of the ascending aorta were severely calcified making valve implantation impossible. Surgical closure without valve substitution was estimated to be associated with a high risk of mortality due...

  10. Supra-aortic interventions for endovascular exclusion of the entire aortic arch.

    Science.gov (United States)

    Andrási, Terézia B; Grossmann, Marius; Zenker, Dieter; Danner, Bernhard C; Schöndube, Friedrich A

    2017-07-01

    Our aim was to analyze the outcomes of endovascular exclusion of the entire aortic arch (proximal landing in zone 0, distal landing in zone III or beyond, after Ishimaru) in which complete surgical debranching of the supra-aortic vessels (I), endovascular supra-aortic revascularization (chimney, fenestrated, or branched grafts) with partial surgical debranching (II), or total endovascular supra-aortic revascularization (III) was additionally performed. Publications describing endovascular repair of the aortic arch (2000-2016) were systematically searched and reviewed. From a total of 53 relevant studies including 1853 patients, only 1021 patients undergoing 35 different total aortic arch procedures were found eligible for further evaluation and included in group I, II, or III (429, 190, and 402 patients, respectively). Overall early mortality was higher in group I vs groups II and III (P = .001; 1 - β = 95.6%) but exceeded in group III (18.6%) and group II (14.0%) vs group I (8.0%; P = .044; 1 - β = 57.4%) for diseases involving zone 0. Mortality was higher in all subgroups treated for zone 0 disease compared with corresponding subgroups treated for zone I to zone III disease. The incidence of cerebral ischemic events was increased in groups I and II vs group III (7.5% and 11% vs 1.7%; P = .0001) and correlated with early mortality (R 2  = .20; P = .033). The incidence of type II endoleaks and endovascular reintervention was similar between groups and correlated with each other (R 2  = .37; P = .004). Type Ia endoleak occurred more often in groups II and III than in group I (7.1% and 12.1% vs 5.8%; P = .023) and correlated with midterm mortality (R 2  = .53; P = .005). Retrograde type A dissection was low in all groups, whereas aneurysm growth was higher in group III (2.6%, 4.2%, 10.7%; P = .002), correlating with midterm mortality (R 2  = .311; P = .009). Surgical revision slightly correlated with surgical complications (R 2  = .18; P = .044

  11. Aortic arch malformations

    Energy Technology Data Exchange (ETDEWEB)

    Kellenberger, Christian J. [University Children' s Hospital, Department of Diagnostic Imaging, Zuerich (Switzerland)

    2010-06-15

    Although anomalies of the aortic arch and its branches are relatively uncommon malformations, they are often associated with congenital heart disease. Isolated lesions may be clinically significant when the airways are compromised by a vascular ring. In this article, the development and imaging appearance of the aortic arch system and its various malformations are reviewed. (orig.)

  12. Imaging in aortic dissection

    International Nuclear Information System (INIS)

    Yu-Qing Liu, M.D.

    1995-01-01

    Aortic dissection (AD) is a catastrophic aortic disease. Imaging techniques play an invaluable role in the diagnostic evaluation and management of patients with AD. Major signs of AD with different imaging modalities are described in this article with a pertinent discussion on guidelines for the optimized approach of imaging study (13 refs.)

  13. Aortic arch malformations

    International Nuclear Information System (INIS)

    Kellenberger, Christian J.

    2010-01-01

    Although anomalies of the aortic arch and its branches are relatively uncommon malformations, they are often associated with congenital heart disease. Isolated lesions may be clinically significant when the airways are compromised by a vascular ring. In this article, the development and imaging appearance of the aortic arch system and its various malformations are reviewed. (orig.)

  14. Imaging in aortic dissection

    Energy Technology Data Exchange (ETDEWEB)

    Yu-Qing Liu, M D [Chinese Academy of Medical Sciences, Beijing, BJ (China). Dept. of Radiology, Fu Wai Hospital and Cardiovascular Inst.

    1996-12-31

    Aortic dissection (AD) is a catastrophic aortic disease. Imaging techniques play an invaluable role in the diagnostic evaluation and management of patients with AD. Major signs of AD with different imaging modalities are described in this article with a pertinent discussion on guidelines for the optimized approach of imaging study (13 refs.).

  15. Evaluation of aortic elastic properties in patients with exaggerated systolic blood pressure response to exercise testing.

    Science.gov (United States)

    Kilicaslan, Baris; Eren, Nihan Kahya; Nazlı, Cem

    2015-01-01

    We aimed to evaluate the aortic elastic properties in subjects with hypertensive response to exercise stress test (HRE). Sixty-six patients were divided into two groups (33 patients in HRE group and 33 patients in normotensive group). Baseline demographic characteristics were similar. The mean aortic stiffness index (ASI) was significantly higher (p=0.001) whereas aortic distensibility (AD) was significantly lower (p=0.029) in patients suggesting HRE. The C-reactive protein levels of patients with HRE was higher in the HRE group (p=0.03). AD was significantly correlated with age (r=-0.406, pHRE.

  16. Stiffness, resilience, compressibility

    Energy Technology Data Exchange (ETDEWEB)

    Leu, Bogdan M. [Argonne National Laboratory, Advanced Photon Source (United States); Sage, J. Timothy, E-mail: jtsage@neu.edu [Northeastern University, Department of Physics and Center for Interdisciplinary Research on Complex Systems (United States)

    2016-12-15

    The flexibility of a protein is an important component of its functionality. We use nuclear resonance vibrational spectroscopy (NRVS) to quantify the flexibility of the heme iron environment in the electron-carrying protein cytochrome c by measuring the stiffness and the resilience. These quantities are sensitive to structural differences between the active sites of different proteins, as illustrated by a comparative analysis with myoglobin. The elasticity of the entire protein, on the other hand, can be probed quantitatively from NRVS and high energy-resolution inelastic X-ray scattering (IXS) measurements, an approach that we used to extract the bulk modulus of cytochrome c.

  17. Valve-sparing aortic root replacement†.

    Science.gov (United States)

    Koolbergen, David R; Manshanden, Johan S J; Bouma, Berto J; Blom, Nico A; Mulder, Barbara J M; de Mol, Bas A J M; Hazekamp, Mark G

    2015-02-01

    To evaluate our results of valve-sparing aortic root replacement and associated (multiple) valve repair. From September 2003 to September 2013, 97 patients had valve-sparing aortic root replacement procedures. Patient records and preoperative, postoperative and recent echocardiograms were reviewed. Median age was 40.3 (range: 13.4-68.6) years and 67 (69.1%) were male. Seven (7.2%) patients were younger than 18 years, the youngest being 13.4 years. Fifty-four (55.7%) had Marfan syndrome, 2 (2.1%) other fibrous tissue diseases, 15 (15.5%) bicuspid aortic valve and 3 (3.1%) had earlier Fallot repair. The reimplantation technique was used in all, with a straight vascular prosthesis in 11 (26-34 mm) and the Valsalva prosthesis in 86 (26-32 mm). Concomitant aortic valve repair was performed in 43 (44.3%), mitral valve repair in 10 (10.3%), tricuspid valve repair in 5 (5.2%) and aortic arch replacement in 3 (3.1%). Mean follow-up was 4.2 ± 2.4 years. Follow-up was complete in all. One 14-year old patient died 1.3 years post-surgery presumably of ventricular arrhythmia. One patient underwent reoperation for aneurysm of the proximal right coronary artery after 4.9 years and 4 patients required aortic valve replacement, 3 of which because of endocarditis after 0.1, 0.8 and 1.3 years and 1 because of cusp prolapse after 3.8 years. No thrombo-embolic complications occurred. Mortality, root reoperation and aortic regurgitation were absent in 88.0 ± 0.5% at 5-year follow-up. Results of valve-sparing root replacement are good, even in association with a high incidence of concomitant valve repair. Valve-sparing aortic root replacement can be performed at a very young age as long as an adult size prosthesis can be implanted. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  18. Uncomplicated obesity is associated with abnormal aortic function assessed by cardiovascular magnetic resonance

    Directory of Open Access Journals (Sweden)

    Channon Keith M

    2008-02-01

    Full Text Available Abstract Aims Obese subjects with insulin resistance and hypertension have abnormal aortic elastic function, which may predispose them to the development of left ventricular dysfunction. We hypothesised that obesity, uncomplicated by other cardiovascular risk factors, is independently associated with aortic function. Methods and results We used magnetic resonance imaging to measure aortic compliance, distensibility and stiffness index in 27 obese subjects (BMI 33 kg/m2 without insulin resistance and with normal cholesterol and blood pressure, and 12 controls (BMI 23 kg/m2. Obesity was associated with reduced aortic compliance (0.9 ± 0.1 vs. 1.5 ± 0.2 mm2/mmHg in controls, p -1 × 10-3, p Conclusion Aortic elastic function is abnormal in obese subjects without other cardiovascular risk factors. These findings highlight the independent importance of obesity in the development of cardiovascular disease.

  19. Why aortic elasticity differs among classical and non-classical mitral valve prolapsed?

    Science.gov (United States)

    Unlu, Murat; Demirkol, Sait; Aparci, Mustafa; Arslan, Zekeriya; Balta, Sevket; Dogan, Umuttan; Kilicarslan, Baris; Ozeke, Ozcan; Celik, Turgay; Iyisoy, Atila

    2014-01-01

    Mitral valve prolapse (MVP) is the most common valvular heart disease and characterized by the displacement of an abnormally thickened mitral valve leaflet into the left atrium during systole. There are two types of MVP, broadly classified as classic (thickness ≥5 mm) and non-classic (thickness elastic properties of the aorta in young male patients with classical and non-classical MVP. In the present study, 63 young adult males (mean age: 22.7 ± 4.2) were included. Patients were divided into classic MVP (n = 27) and non-classic MVP (n = 36) groups. Aortic strain, aortic distensibility and aortic stiffness index were calculated by using aortic diameters obtained by echocardiography and blood pressures measured by sphygmomanometer. There was no significant difference between the groups in terms of age, body mass index, left ventricular mass and ejection fraction. When comparing the MVP group it was found that aortic strain and aortic distensibility were increased (p = 0.0027, p = 0.016, respectively) whereas the aortic stiffness index was decreased (p = 0.06) in the classical MVP group. We concluded that the elastic properties of the aorta is increased in patients with classic MVP. Further large scale studies should be performed to understand of morphological and physiological properties of the aorta in patients with MVP.

  20. Bovine aortic arch with supravalvular aortic stenosis.

    Science.gov (United States)

    Idhrees, Mohammed; Cherian, Vijay Thomas; Menon, Sabarinath; Mathew, Thomas; Dharan, Baiju S; Jayakumar, K

    2016-09-01

    A 5-year-old boy was diagnosed to have supravalvular aortic stenosis (SVAS). On evaluation of CT angiogram, there was associated bovine aortic arch (BAA). Association of BAA with SVAS has not been previously reported in literature, and to best of our knowledge, this is the first case report of SVAS with BAA. Recent studies show BAA as a marker for aortopathy. SVAS is also an arteriopathy. In light of this, SVAS can also possibly be a manifestation of aortopathy associated with BAA. Copyright © 2015 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

  1. Bovine aortic arch with supravalvular aortic stenosis

    Directory of Open Access Journals (Sweden)

    Mohammed Idhrees

    2016-09-01

    Full Text Available A 5-year-old boy was diagnosed to have supravalvular aortic stenosis (SVAS. On evaluation of CT angiogram, there was associated bovine aortic arch (BAA. Association of BAA with SVAS has not been previously reported in literature, and to best of our knowledge, this is the first case report of SVAS with BAA. Recent studies show BAA as a marker for aortopathy. SVAS is also an arteriopathy. In light of this, SVAS can also possibly be a manifestation of aortopathy associated with BAA.

  2. Pharmacological modulation of arterial stiffness.

    LENUS (Irish Health Repository)

    Boutouyrie, Pierre

    2011-09-10

    Arterial stiffness has emerged as an important marker of cardiovascular risk in various populations and reflects the cumulative effect of cardiovascular risk factors on large arteries, which in turn is modulated by genetic background. Arterial stiffness is determined by the composition of the arterial wall and the arrangement of these components, and can be studied in humans non-invasively. Age and distending pressure are two major factors influencing large artery stiffness. Change in arterial stiffness with drugs is an important endpoint in clinical trials, although evidence for arterial stiffness as a therapeutic target still needs to be confirmed. Drugs that independently affect arterial stiffness include antihypertensive drugs, mostly blockers of the renin-angiotensin-aldosterone system, hormone replacement therapy and some antidiabetic drugs such as glitazones. While the quest continues for \\'de-stiffening drugs\\

  3. Relationship of Aortic Wall Distensibility to Mitral and Aortic Valve Calcification: The Multi-Ethnic Study of Atherosclerosis.

    Science.gov (United States)

    Cohoon, Kevin P; Criqui, Michael H; Budoff, Matthew J; Lima, Joao A; Blaha, Michael J; Decker, Paul A; Durazo, Ramon; Liu, Kiang; Kramer, Holly

    2018-05-01

    Data are limited on whether valvular calcification is associated with aortic wall stiffness. We tested whether aortic valve calcification (AVC) and/or mitral valve calcification (MVC) is inversely associated with aortic distensibility (AD). Cross-sectional study conducted in a subset of the Multi-Ethnic Study of Atherosclerosis (MESA) included 3676 MESA participants aged 44 to 84 years with AD measured with magnetic resonance imaging and with AVC and MVC measured with noncontrast cardiac computed tomography scans. Both AVC and MVC were divided into 3 categories: zero, AVC and MVC, while 6% (n = 211) and 4% (n = 156) had low, and 6% (n = 209) and 4% (n = 155) had high values of AVC and MVC, respectively. The AVC was independently associated with AD after adjusting for age, gender, and ethnicity ( P = .035). No association was noted between AVC groups and AD after adjustment for all covariates or MVC groups and AD in any model.

  4. Amiloride Improves Endothelial Function and Reduces Vascular Stiffness in Female Mice Fed a Western Diet

    Directory of Open Access Journals (Sweden)

    Luis A. Martinez-Lemus

    2017-06-01

    Full Text Available Obese premenopausal women lose their sex related cardiovascular disease protection and develop greater arterial stiffening than age matched men. In female mice, we have shown that consumption of a Western diet (WD, high in fat and refined sugars, is associated with endothelial dysfunction and vascular stiffening, which occur via activation of mineralocorticoid receptors and associated increases in epithelial Na+ channel (ENaC activity on endothelial cells (EnNaC. Herein our aim was to determine the effect that reducing EnNaC activity with a very-low-dose of amiloride would have on decreasing endothelial and arterial stiffness in young female mice consuming a WD. To this end, we fed female mice either a WD or control diet and treated them with or without a very-low-dose of the ENaC-inhibitor amiloride (1 mg/kg/day in the drinking water for 20 weeks beginning at 4 weeks of age. Mice consuming a WD were heavier and had greater percent body fat, proteinuria, and aortic stiffness as assessed by pulse-wave velocity than those fed control diet. Treatment with amiloride did not affect body weight, body composition, blood pressure, urinary sodium excretion, or insulin sensitivity, but significantly reduced the development of endothelial and aortic stiffness, aortic fibrosis, aortic oxidative stress, and mesenteric resistance artery EnNaC abundance and proteinuria in WD-fed mice. Amiloride also improved endothelial-dependent vasodilatory responses in the resistance arteries of WD-fed mice. These results indicate that a very-low-dose of amiloride, not affecting blood pressure, is sufficient to improve endothelial function and reduce aortic stiffness in female mice fed a WD, and suggest that EnNaC-inhibition may be sufficient to ameliorate the pathological vascular stiffening effects of WD-induced obesity in females.

  5. Dynamic stiffness of suction caissons

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Liingaard, Morten; Andersen, Lars

    The purpose of this report is to evaluate the dynamic soil-structure interaction of suction caissons for offshore wind turbines. The investigation is limited to a determination of the vertical dynamic stiffness of suction caissons. The soil surrounding the foundation is homogenous with linear...... viscoelastic properties. The dynamic stiffness of the suction caisson is expressed by dimensionless frequency-dependent dynamic stiffness coefficients corresponding to the vertical degree of freedom. The dynamic stiffness coefficients for the foundations are evaluated by means of a dynamic three...

  6. Trabecular meshwork stiffness in glaucoma.

    Science.gov (United States)

    Wang, Ke; Read, A Thomas; Sulchek, Todd; Ethier, C Ross

    2017-05-01

    Alterations in stiffness of the trabecular meshwork (TM) may play an important role in primary open-angle glaucoma (POAG), the second leading cause of blindness. Specifically, certain data suggest an association between elevated intraocular pressure (IOP) and increased TM stiffness; however, the underlying link between TM stiffness and IOP remains unclear and requires further study. We here first review the literature on TM stiffness measurements, encompassing various species and based on a number of measurement techniques, including direct approaches such as atomic force microscopy (AFM) and uniaxial tension tests, and indirect methods based on a beam deflection model. We also briefly review the effects of several factors that affect TM stiffness, including lysophospholipids, rho-kinase inhibitors, cytoskeletal disrupting agents, dexamethasone (DEX), transforming growth factor-β 2 (TGF-β 2 ), nitric oxide (NO) and cellular senescence. We then describe a method we have developed for determining TM stiffness measurement in mice using a cryosection/AFM-based approach, and present preliminary data on TM stiffness in C57BL/6J and CBA/J mouse strains. Finally, we investigate the relationship between TM stiffness and outflow facility between these two strains. The method we have developed shows promise for further direct measurements of mouse TM stiffness, which may be of value in understanding mechanistic relations between outflow facility and TM biomechanical properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Limit cycles and stiffness control with variable stiffness actuators

    NARCIS (Netherlands)

    Carloni, Raffaella; Marconi, L.

    2012-01-01

    Variable stiffness actuators realize highly dynamic systems, whose inherent mechanical compliance can be properly exploited to obtain a robust and energy-efficient behavior. The paper presents a control strategy for variable stiffness actuators with the primarily goal of tracking a limit cycle

  8. Reoperative aortic root replacement: Outcome in a contemporary series.

    Science.gov (United States)

    Esaki, Jiro; Leshnower, Bradley G; Binongo, Jose N; Lasanajak, Yi; McPherson, LaRonica; Thourani, Vinod H; Chen, Edward P

    2017-09-01

    Reoperative aortic root replacement is a challenging procedure associated with significant mortality and morbidity. The purpose of this study was to investigate the outcomes of reoperative aortic root replacement when performed in a number of complex clinical settings and to identify risk factors for operative mortality and long-term survival. From 2006 to 2015, 280 consecutive patients at an academic center underwent reoperative aortic root replacement after a variety of previous aortic or cardiac operations. Logistic regression and extended Cox proportional hazards regression analyses were used to determine risk factors for operative mortality and long-term survival, respectively. The mean age of patients was 52.5 ± 14.1 years. Prior operations included proximal aortic replacement in 113 patients, valve surgery in 162 patients, and coronary artery bypass grafting in 46 patients. Concomitant procedures included arch replacement in 135 patients, coronary artery bypass grafting in 68 patients, and mitral valve repair/replacement in 18 patients. Operative mortality was 14.3%. Five-year survival was 74.0%. Univariable analysis did not find previous root replacement, prior proximal aortic surgery, and concomitant arch replacement to be risk factors for operative mortality. In the multivariable analysis, chronic lung disease, prior myocardial infarction, and concomitant mitral valve surgery were risk factors for operative mortality. Age, peripheral artery disease, emergency, and concomitant mitral valve surgery were risk factors for mortality in the late phase. Reoperative aortic root replacement represents complex procedures carrying significant morbidity and mortality. Chronic lung disease, prior myocardial infarction, and concomitant mitral valve surgery were risk factors for operative mortality. Age, peripheral artery disease, emergency, and concomitant mitral valve surgery were risk factors for long-term mortality. Copyright © 2017 The American Association for

  9. Effects of acute aerobic exercise on arterial stiffness and cerebrovascular pulsatility in adults with and without hypertension.

    Science.gov (United States)

    Lefferts, Wesley K; DeBlois, Jacob P; Receno, Candace N; Barreira, Tiago V; Brutsaert, Tom D; Carhart, Robert L; Heffernan, Kevin S

    2018-04-19

    Stiffer central arteries, as seen in hypertension (HTN), foster transmission of pulsatile hemodynamics into fragile cerebral vessels. Aerobic exercise is recommended for adults with HTN, but its effects on arterial stiffness and pulsatility in this group are unclear. This study sought to investigate the effect of acute aerobic exercise on arterial stiffness and cerebrovascular pulsatility in 30 adults with treated HTN and 30 age, sex, and BMI-matched adults without HTN (56 ± 6 years, BMI 28.2 ± 2.9 kg/m; 28 women). Patients underwent hemodynamic measures before/after 30-min cycling (≈55% peak oxygen consumption). Aortic stiffness was measured using carotid-femoral pulse wave velocity, and carotid artery stiffness was assessed with β-stiffness via ultrasound. Aortic/carotid pulse pressure (aortic via radial generalized transfer function) was measured by tonometry and calibrated to brachial mean pressure and diastolic pressure. Carotid/middle cerebral artery (MCA) blood velocity pulsatility indices were measured using Doppler. Carotid wave intensity analysis was used to derive forward wave intensity (W1). Exercise impacted hemodynamics similarly in HTN compared to no-HTN. Carotid-femoral pulse wave velocity, MCA pulsatility index, carotid pulsatility index, and W1 increased similarly after exercise in both groups (P < 0.05). Carotid pulse pressure and β-stiffness were unaltered after exercise. Postexercise changes in W1 were positively associated with carotid pulsatility index, which was further associated with MCA pulsatility index. These data suggest adults with treated HTN experience similar increases in aortic stiffness and cerebrovascular hemodynamic pulsatility during early recovery from acute aerobic exercise as their counterparts without HTN.

  10. Sex-specific genetic determinants for arterial stiffness in Dahl salt-sensitive hypertensive rats.

    Science.gov (United States)

    Decano, Julius L; Pasion, Khristine A; Black, Nicole; Giordano, Nicholas J; Herrera, Victoria L; Ruiz-Opazo, Nelson

    2016-01-11

    Arterial stiffness is an independent predictor of cardiovascular outcomes in hypertensive patients including myocardial infarction, fatal stroke, cerebral micro-bleeds which predicts cerebral hemorrhage in hypertensive patients, as well as progression to hypertension in non-hypertensive subjects. The association between arterial stiffness and various cardiovascular outcomes (coronary heart disease, stroke) remains after adjusting for age, sex, blood pressure, body mass index and other known predictors of cardiovascular disease, suggesting that arterial stiffness, measured via carotid-femoral pulse wave velocity, has a better predictive value than each of these factors. Recent evidence shows that arterial stiffening precedes the onset of high blood pressure; however their molecular genetic relationship (s) and sex-specific determinants remain uncertain. We investigated whether distinct or shared genetic determinants might underlie susceptibility to arterial stiffening in male and female Dahl salt-sensitive rats. Thus, we performed a genome-wide scan for quantitative trait loci (QTLs) affecting arterial stiffness in six-week old F2 (Dahl S x R)-intercross male and female rats characterized for abdominal aortic pulse wave velocity and aortic strain by high-resolution ultrasonography. We detected five highly significant QTLs affecting aortic stiffness: two interacting QTLs (AS-m1 on chromosome 4 and AS-m2 on chromosome16, LOD 8.8) in males and two distinct interacting QTLs (AS-f1 on chromosome 9 and AS-f2 on chromosome11, LOD 8.9) in females affecting pulse wave velocity. One QTL (AS-1 on chromosome 3, LOD 4.3) was found to influence aortic strain in a sex-independent manner. None of these arterial stiffness QTLs co-localized with previously reported blood pressure QTLs detected in equivalent genetic intercrosses. These data reveal sex-specific genetic determinants for aortic pulse wave velocity and suggest distinct polygenic susceptibility for arterial stiffness and

  11. Aneurysm growth after late conversion of thoracic endovascular aortic repair

    Directory of Open Access Journals (Sweden)

    Hirofumi Kasahara

    2015-01-01

    Full Text Available A 69-year-old man underwent thoracic endovascular aortic repair of a descending aortic aneurysm. Three years later, he developed impending rupture due to aneurysmal expansion that included the proximal landing zone. Urgent open surgery was performed via lateral thoracotomy, and a Dacron graft was sewn to the previous stent graft distally with Teflon felt reinforcement. Postoperatively, four sequential computed tomography scans demonstrated that the aneurysm was additionally increasing in size probably due to continuous hematoma production, suggesting a possibility of endoleaks. This case demonstrates the importance of careful radiologic surveillance after endovascular repair, and also after partial open conversion.

  12. Paradoxical aortic stenosis: A systematic review.

    Science.gov (United States)

    Cavaca, Rita; Teixeira, Rogério; Vieira, Maria João; Gonçalves, Lino

    2017-04-01

    Aortic stenosis (AS) is a complex systemic valvular and vascular disease with a high prevalence in developed countries. The new entity "paradoxical low-flow, low-gradient aortic stenosis" refers to cases in which patients have severe AS based on assessment of aortic valve area (AVA) (≤1 cm 2 ) or indexed AVA (≤0.6 cm 2 /m 2 ), but paradoxically have a low mean transvalvular gradient (<40 mmHg) and a low stroke volume index (≤35 ml/m 2 ), despite preserved left ventricular ejection fraction (≥50%). A search was carried out in the PubMed database on paradoxical AS for the period 2007-2014. A total of 57 articles were included for this review. The prevalence of paradoxical AS ranged from 3% to 35% of the population with severe degenerative AS. It was more frequent in females and in older patients. Paradoxical AS was associated with characteristic left ventricular remodeling as well as an increase in systemic arterial stiffness. It was noted that there may be errors and inaccuracies in the calculation of AVA by the continuity equation, which could erroneously suggest the paradoxical phenotype. There are new diagnostic methods to facilitate the study of AS, such as aortic valve calcium score, valvuloarterial impedance and the longitudinal mechanics of the left ventricle. With regard to its natural history, it is not clear whether paradoxical AS corresponds to an advance stage of the disease or if paradoxical AS patients have a distinct phenotype with specific characteristics. Valve replacement, either surgical or percutaneous, may be indicated in patients with severe and symptomatic paradoxical AS. Copyright © 2016 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

  13. Free androgen index as a determinant of arterial stiffness in menopause: a mediation analysis.

    Science.gov (United States)

    Lambrinoudaki, Irene; Georgiopoulos, Georgios A; Athanasouli, Fani; Armeni, Elena; Rizos, Demetrios; Augoulea, Areti; Chatzidou, Sofia; Koutli, Evangelia; Makris, Nikolaos; Kanakakis, Ioannis; Stamatelopoulos, Kimon

    2017-06-01

    Associations of endogenous androgens in menopause with blood pressure (BP) and indices of arterial stiffness are reported, but directional relationships are not clear. Structural equation modeling is a contemporary statistical method, which allows assessment of such relationships and improves pathway understanding. We recruited 411 consecutive apparently healthy postmenopausal women who underwent noninvasive vascular evaluation. This included pulse wave analysis (aortic pressures and arterial wave reflections [augmentation index]), measurement of aortic stiffness by pulse wave velocity (PWV), stiffness index (SI), and flow-mediated dilatation. A cumulative marker combining PWV and SI (combined local and aortic arterial stiffness [CAS]) was also assessed. Free androgen index (FAI) was calculated from circulating total testosterone and sex hormone-binding globulin. FAI was an independent determinant of systolic BP (SBP) (P = 0.032), SI (P = 0.042), and PWV (P = 0.027). Under structural equation modeling analysis, FAI was a direct predictor for PWV (beta = 0.149, P = 0.014), SI (beta = 0.154, P = 0.022), and CAS (beta = 0.193, P = 0.02), whereas SBP was a parallel mediator of androgen's vascular effects on PWV (beta = 0.280, P stiffness via flow-mediated dilatation was not established. FAI was not a determinant of augmentation index. In healthy postmenopausal women, FAI was directly associated with PWV, SI, and CAS. FAI also directly correlated with SBP, which in turn concurrently increased PWV and CAS. The directional correlations found herein, imply that endogenous androgens may be causally associated with indices of arterial stiffness both directly and indirectly. This hypothesis should be confirmed in further studies with causal design.

  14. Type A aortic dissection: Are there CT signs suggestive of valvular involvement?

    Energy Technology Data Exchange (ETDEWEB)

    Platon, Alexandra, E-mail: alexandra.platon@hcuge.ch [Department of Radiology, Emergency Radiology Unit, University Hospital of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Geneva (Switzerland); Bernard, Stephane; Perrin, Nils [Department of Radiology, Emergency Radiology Unit, University Hospital of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Geneva (Switzerland); Murith, Nicolas [Division of Cardiovascular Surgery, University Hospital of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Geneva (Switzerland); John, Gregor [Department of Internal medicine/Geriatrics and Rehabilitation, University Hospital of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Geneva (Switzerland); Department of Internal Medicine, Hôpital neuchâtelois, 2300 La Chaux-de-Fonds (Switzerland); Perneger, Thomas [Division of Clinical Epidemiology, University Hospital of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Geneva (Switzerland); Rutschmann, Olivier T. [Division of Emergency Medicine, University Hospitals of Geneva and School of Medicine, 4 rue Gabrielle-Perret-Gentil, 1211, Geneva (Switzerland); Poletti, Pierre-Alexandre [Department of Radiology, Emergency Radiology Unit, University Hospital of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Geneva (Switzerland)

    2016-11-15

    Highlights: • Non-ECG gated CT rarely shows valve involvement in type A aortic dissection. • Diameters of the aortic root in type A aortic dissection were measured on initial CT. • Sinus of Valsalva diameter >45 mm is 100% specific to predict aortic valve involvement. - Abstract: Aim: To identify the predictive signs of aortic valve involvement on the non-electrocardiogram (ECG)-gated admission computed tomography (CT) of patients with Type A aortic dissection (AD) according to the Stanford classification. Materials and methods: We retrospectively analyzed the non-ECG-gated CT examinations of patients admitted to the emergency department who underwent surgery for Type A AD over a period of 4 years. The diameter of the following structures was calculated as the mean of the smallest and largest diameters (mm) measured in two different planes: aortic annulus, sinus of Valsalva, sinotubular junction, and proximal ascending aorta. These parameters were compared against operative reports in order to determine whether they were predictive of aortic valve involvement. Results: In total, 20 patients (13 men and 7 women) of a mean age of 59.5 years (29–80) were included, 55% of patients (11/20) having surgically proven valvular involvement. The mean diameters (in mm) of the aortic annulus, sinus of Valsalva, sinotubular junction and proximal ascending aorta in the group with (and without, respectively) valvular involvement was 27.7 (26.7), 44.3 (38.1), 42.6 (36.6), and 47.8 (45.9). Only the measurement of the mean diameter of the sinuses of Valsalva was significantly predictive (p = 0.02) of aortic valve involvement. Conclusion: Our findings suggest that measuring the diameter of the sinuses of Valsalva on non-ECG-gated admission CT examinations allows for predicting aortic valve involvement in Type A AD patients.

  15. Type A aortic dissection: Are there CT signs suggestive of valvular involvement?

    International Nuclear Information System (INIS)

    Platon, Alexandra; Bernard, Stephane; Perrin, Nils; Murith, Nicolas; John, Gregor; Perneger, Thomas; Rutschmann, Olivier T.; Poletti, Pierre-Alexandre

    2016-01-01

    Highlights: • Non-ECG gated CT rarely shows valve involvement in type A aortic dissection. • Diameters of the aortic root in type A aortic dissection were measured on initial CT. • Sinus of Valsalva diameter >45 mm is 100% specific to predict aortic valve involvement. - Abstract: Aim: To identify the predictive signs of aortic valve involvement on the non-electrocardiogram (ECG)-gated admission computed tomography (CT) of patients with Type A aortic dissection (AD) according to the Stanford classification. Materials and methods: We retrospectively analyzed the non-ECG-gated CT examinations of patients admitted to the emergency department who underwent surgery for Type A AD over a period of 4 years. The diameter of the following structures was calculated as the mean of the smallest and largest diameters (mm) measured in two different planes: aortic annulus, sinus of Valsalva, sinotubular junction, and proximal ascending aorta. These parameters were compared against operative reports in order to determine whether they were predictive of aortic valve involvement. Results: In total, 20 patients (13 men and 7 women) of a mean age of 59.5 years (29–80) were included, 55% of patients (11/20) having surgically proven valvular involvement. The mean diameters (in mm) of the aortic annulus, sinus of Valsalva, sinotubular junction and proximal ascending aorta in the group with (and without, respectively) valvular involvement was 27.7 (26.7), 44.3 (38.1), 42.6 (36.6), and 47.8 (45.9). Only the measurement of the mean diameter of the sinuses of Valsalva was significantly predictive (p = 0.02) of aortic valve involvement. Conclusion: Our findings suggest that measuring the diameter of the sinuses of Valsalva on non-ECG-gated admission CT examinations allows for predicting aortic valve involvement in Type A AD patients.

  16. Arterial stiffness &Sri Lankan chronic kidney disease of unknown origin.

    Science.gov (United States)

    Gifford, Fiona; Kimmitt, Robert; Herath, Chula; Webb, David J; Melville, Vanessa; Siribaddana, Sisira; Eddleston, Michael; Dhaun, Neeraj

    2016-09-02

    Chronic kidney disease (CKD) is common and independently associated with cardiovascular disease (CVD). Arterial stiffness contributes to CVD risk in CKD. In many developing countries a considerable proportion of CKD remains unexplained, termed CKDu. We assessed arterial stiffness in subjects with Sri Lankan CKDu, in matched controls without CKD and in those with defined CKD. Aortic blood pressure (BP), pulse wave velocity (PWV) and augmentation index (AIx) were assessed in 130 subjects (50 with CKDu, 45 with CKD and 35 without CKD) using the validated TensioMed™ Arteriograph monitor. Brachial and aortic BP was lower in controls than in CKDu and CKD subjects but no different between CKDu and CKD. Controls had a lower PWV compared to subjects with CKDu and CKD. Despite equivalent BP and renal dysfunction, CKDu subjects had a lower PWV than those with CKD (8.7 ± 1.5 vs. 9.9 ± 2.2 m/s, p CKDu vs. CKD: 6.7 ± 0.9 vs. 8.7 ± 1.5 vs. 10.4 ± 1.5 m/s, p CKDu is associated with less arterial stiffening than defined causes of CKD. Whether this translates to lower cardiovascular morbidity and mortality long term is unclear and should be the focus of future studies.

  17. Artificial muscles with adjustable stiffness

    International Nuclear Information System (INIS)

    Mutlu, Rahim; Alici, Gursel

    2010-01-01

    This paper reports on a stiffness enhancement methodology based on using a suitably designed contact surface with which cantilevered-type conducting polymer bending actuators are in contact during operation. The contact surface constrains the bending behaviour of the actuators. Depending on the topology of the contact surface, the resistance of the polymer actuators to deformation, i.e. stiffness, is varied. As opposed to their predecessors, these polymer actuators operate in air. Finite element analysis and modelling are used to quantify the effect of the contact surface on the effective stiffness of a trilayer cantilevered beam, which represents a one-end-free, the-other-end-fixed polypyrrole (PPy) conducting polymer actuator under a uniformly distributed load. After demonstrating the feasibility of the adjustable stiffness concept, experiments were conducted to determine the stiffness of bending-type conducting polymer actuators in contact with a range (20–40 mm in radius) of circular contact surfaces. The numerical and experimental results presented demonstrate that the stiffness of the actuators can be varied using a suitably profiled contact surface. The larger the radius of the contact surface is, the higher is the stiffness of the polymer actuators. The outcomes of this study suggest that, although the stiffness of the artificial muscles considered in this study is constant for a given geometric size, and electrical and chemical operation conditions, it can be changed in a nonlinear fashion to suit the stiffness requirement of a considered application. The stiffness enhancement methodology can be extended to other ionic-type conducting polymer actuators

  18. Ambulatory (24 h) blood pressure and arterial stiffness measurement in Marfan syndrome patients: a case control feasibility and pilot study.

    Science.gov (United States)

    Hillebrand, Matthias; Nouri, Ghazaleh; Hametner, Bernhard; Parragh, Stephanie; Köster, Jelena; Mortensen, Kai; Schwarz, Achim; von Kodolitsch, Yskert; Wassertheurer, Siegfried

    2016-05-06

    The aim of this work is the investigation of measures of ambulatory brachial and aortic blood pressure and indices of arterial stiffness and aortic wave reflection in Marfan patients. A case-control study was conducted including patients with diagnosed Marfan syndrome following Ghent2 nosology and healthy controls matched for sex, age and daytime brachial systolic blood pressure. For each subject a 24 h ambulatory blood pressure and 24 h pulse wave analysis measurement was performed. All parameters showed a circadian pattern whereby pressure dipping was more pronounced in Marfan patients. During daytime only Marfan patients with aortic root surgery showed increased pulse wave velocity. In contrast, various nighttime measurements, wave reflection determinants and circadian patterns showed a significant difference. The findings of our study provide evidence that ambulatory measurement of arterial stiffness parameters is feasible and that these determinants are significantly different in Marfan syndrome patients compared to controls in particular at nighttime. Further investigation is therefore indicated.

  19. Surgical treatment of pararenal aortic aneurysms in the elderly.

    Science.gov (United States)

    Illuminati, G; D'Urso, A; Ceccanei, G; Caliò, F; Vietri, F

    2007-12-01

    Until fenestrated endografts will become the standard treatment of pararenal aortic aneurysms, open surgical repair will currently be employed for the repair of this condition. Suprarenal aortic control and larger surgical dissection represent additional technical requirements for the treatment of pararenal aneurysms compared to those of open infrarenal aortic aneurysms, which may be followed by an increased operative mortality and morbidity rate. As this may be especially true when dealing with pararenal aneurysms in an elderly patients' population, we decided to retrospectively review our results of open pararenal aortic aneurysm repair in elderly patients, in order to compare them with those reported in the literature. Twenty-one patients over 75 years of age were operated on for pararenal aortic aneurysms in a ten-year period. Exposure of the aorta was obtained by means of a retroperitoneal access, through a left flank incision on the eleventh rib. When dealing with interrenal aortic aneurysm the left renal artery was revascularized with a retrograde bypass arising from the aortic graft, proximally bevelled on the ostium of the right renal artery. Two patients died of acute intestinal ischemia, yielding a postoperative mortality of 9.5%. Nonfatal complications included 2 pleural effusions, a transitory rise in postoperative serum creatinine levels in 3 cases, and one retroperitoneal hematoma. Mean renal ischemia time was 23 min, whereas mean visceral ischemia time was 19 min. Mean inhospital stay was 11 days. Pararenal aortic aneurysms in the elderly can be surgically repaired with results that are similar to those obtained in younger patients.

  20. Unicuspid aortic valve disease: a magnetic resonance imaging study

    International Nuclear Information System (INIS)

    Debl, K.; Buchner, S.; Heinicke, N.; Riegger, G.; Luchner, A.; Djavidani, B.; Poschenrieder, F.; Feuerbach, S.; Schmid, C.; Kobuch, R.

    2008-01-01

    Purpose: congenitally malformed aortic valves are a common finding in adults with aortic valve disease. Most of these patients have bicuspid aortic valve disease. Unicuspid aortic valve disease (UAV) is rare. The aim of our study was to describe valve morphology and the dimensions of the proximal aorta in a cohort of 12 patients with UAV in comparison to tricuspid aortic valve disease (TAV) using magnetic resonance imaging (MRI). Materials and methods/results: MRI studies were performed on a 1.5 T scanner in a total of 288 consecutive patients with aortic valve disease. 12 aortic valves were retrospectively classified as UAV. Annulus areas and dimensions of the thoracic aorta were retrospectively compared to a cohort of 103 patients with TAV. In UAV, valve morphology was unicuspid unicommissural with a posterior commissure in all patients. Mean annulus areas and mean diameters of the ascending aorta were significantly greater in UAV compared to TAV (12.6 ± 4.7 cm 2 vs. 8.7 ± 2.3 cm 2 , p < 0.01 and 4.6 ± 0.7 cm vs. 3.6 ± 0.5 cm, p < 0.0001, respectively), while no differences were observed in the mean diameters of the aortic arch (2.3 ± 0.6 cm vs. 2.3 ± 0.4 cm, p = 0.69). The diameters of the descending aorta were slightly smaller in UAV compared to TAV (2.2 ± 0.5 cm vs. 2.6 ± 0.3 cm, p < 0.05). (orig.)

  1. Unicuspid aortic valve disease: a magnetic resonance imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Debl, K.; Buchner, S.; Heinicke, N.; Riegger, G.; Luchner, A. [Klinik und Poliklinik fuer Innere Medizin II, Universitaetsklinikum Regensburg (Germany); Djavidani, B.; Poschenrieder, F.; Feuerbach, S. [Inst. fuer Roentgendiagnostik, Universitaetsklinikum Regensburg (Germany); Schmid, C.; Kobuch, R. [Klinik und Poliklinik fuer Herz-, Thorax- und herznahe Gefaesschirurgie, Universitaetsklinikum Regensburg (Germany)

    2008-11-15

    Purpose: congenitally malformed aortic valves are a common finding in adults with aortic valve disease. Most of these patients have bicuspid aortic valve disease. Unicuspid aortic valve disease (UAV) is rare. The aim of our study was to describe valve morphology and the dimensions of the proximal aorta in a cohort of 12 patients with UAV in comparison to tricuspid aortic valve disease (TAV) using magnetic resonance imaging (MRI). Materials and methods/results: MRI studies were performed on a 1.5 T scanner in a total of 288 consecutive patients with aortic valve disease. 12 aortic valves were retrospectively classified as UAV. Annulus areas and dimensions of the thoracic aorta were retrospectively compared to a cohort of 103 patients with TAV. In UAV, valve morphology was unicuspid unicommissural with a posterior commissure in all patients. Mean annulus areas and mean diameters of the ascending aorta were significantly greater in UAV compared to TAV (12.6 {+-} 4.7 cm{sup 2} vs. 8.7 {+-} 2.3 cm{sup 2}, p < 0.01 and 4.6 {+-} 0.7 cm vs. 3.6 {+-} 0.5 cm, p < 0.0001, respectively), while no differences were observed in the mean diameters of the aortic arch (2.3 {+-} 0.6 cm vs. 2.3 {+-} 0.4 cm, p = 0.69). The diameters of the descending aorta were slightly smaller in UAV compared to TAV (2.2 {+-} 0.5 cm vs. 2.6 {+-} 0.3 cm, p < 0.05). (orig.)

  2. Proximity credentials: A survey

    International Nuclear Information System (INIS)

    Wright, L.J.

    1987-04-01

    Credentials as a means of identifying individuals have traditionally been a photo badge and more recently, the coded credential. Another type of badge, the proximity credential, is making inroads in the personnel identification field. This badge can be read from a distance instead of being veiewed by a guard or inserted into a reading device. This report reviews proximity credentials, identifies the companies marketing or developing proximity credentials, and describes their respective credentials. 3 tabs

  3. Proximal Probes Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Proximal Probes Facility consists of laboratories for microscopy, spectroscopy, and probing of nanostructured materials and their functional properties. At the...

  4. Arterial stiffness and cognitive impairment.

    Science.gov (United States)

    Li, Xiaoxuan; Lyu, Peiyuan; Ren, Yanyan; An, Jin; Dong, Yanhong

    2017-09-15

    Arterial stiffness is one of the earliest indicators of changes in vascular wall structure and function and may be assessed using various indicators, such as pulse-wave velocity (PWV), the cardio-ankle vascular index (CAVI), the ankle-brachial index (ABI), pulse pressure (PP), the augmentation index (AI), flow-mediated dilation (FMD), carotid intima media thickness (IMT) and arterial stiffness index-β. Arterial stiffness is generally considered an independent predictor of cardiovascular and cerebrovascular diseases. To date, a significant number of studies have focused on the relationship between arterial stiffness and cognitive impairment. To investigate the relationships between specific arterial stiffness parameters and cognitive impairment, elucidate the pathophysiological mechanisms underlying the relationship between arterial stiffness and cognitive impairment and determine how to interfere with arterial stiffness to prevent cognitive impairment, we searched PUBMED for studies regarding the relationship between arterial stiffness and cognitive impairment that were published from 2000 to 2017. We used the following key words in our search: "arterial stiffness and cognitive impairment" and "arterial stiffness and cognitive impairment mechanism". Studies involving human subjects older than 30years were included in the review, while irrelevant studies (i.e., studies involving subjects with comorbid kidney disease, diabetes and cardiac disease) were excluded from the review. We determined that arterial stiffness severity was positively correlated with cognitive impairment. Of the markers used to assess arterial stiffness, a higher PWV, CAVI, AI, IMT and index-β and a lower ABI and FMD were related to cognitive impairment. However, the relationship between PP and cognitive impairment remained controversial. The potential mechanisms linking arterial stiffness and cognitive impairment may be associated with arterial pulsatility, as greater arterial pulsatility

  5. Stiffness of desiccating insect wings

    International Nuclear Information System (INIS)

    Mengesha, T E; Vallance, R R; Mittal, R

    2011-01-01

    The stiffness of insect wings is typically determined through experimental measurements. Such experiments are performed on wings removed from insects. However, the wings are subject to desiccation which typically leads to an increase in their stiffness. Although this effect of desiccation is well known, a comprehensive study of the rate of change in stiffness of desiccating insect wings would be a significant aid in planning experiments as well as interpreting data from such experiments. This communication presents a comprehensive experimental analysis of the change in mass and stiffness of gradually desiccating forewings of Painted Lady butterflies (Vanessa cardui). Mass and stiffness of the forewings of five butterflies were simultaneously measured every 10 min over a 24 h period. The averaged results show that wing mass declined exponentially by 21.1% over this time period with a time constant of 9.8 h, while wing stiffness increased linearly by 46.2% at a rate of 23.4 μN mm -1 h -1 . For the forewings of a single butterfly, the experiment was performed over a period of 1 week, and the results show that wing mass declined exponentially by 52.2% with a time constant of 30.2 h until it reached a steady-state level of 2.00 mg, while wing stiffness increased exponentially by 90.7% until it reached a steady-state level of 1.70 mN mm -1 . (communication)

  6. Stiffness of desiccating insect wings

    Energy Technology Data Exchange (ETDEWEB)

    Mengesha, T E; Vallance, R R [Department of Mechanical Engineering, The George Washington University, 738 Phillips Hall, 801 22nd St NW, Washington, DC 20052 (United States); Mittal, R, E-mail: vallance@gwu.edu [Department of Mechanical Engineering, Johns Hopkins University, 126 Latrobe Hall, 3400 N Charles Street, Baltimore, MD 21218 (United States)

    2011-03-15

    The stiffness of insect wings is typically determined through experimental measurements. Such experiments are performed on wings removed from insects. However, the wings are subject to desiccation which typically leads to an increase in their stiffness. Although this effect of desiccation is well known, a comprehensive study of the rate of change in stiffness of desiccating insect wings would be a significant aid in planning experiments as well as interpreting data from such experiments. This communication presents a comprehensive experimental analysis of the change in mass and stiffness of gradually desiccating forewings of Painted Lady butterflies (Vanessa cardui). Mass and stiffness of the forewings of five butterflies were simultaneously measured every 10 min over a 24 h period. The averaged results show that wing mass declined exponentially by 21.1% over this time period with a time constant of 9.8 h, while wing stiffness increased linearly by 46.2% at a rate of 23.4 {mu}N mm{sup -1} h{sup -1}. For the forewings of a single butterfly, the experiment was performed over a period of 1 week, and the results show that wing mass declined exponentially by 52.2% with a time constant of 30.2 h until it reached a steady-state level of 2.00 mg, while wing stiffness increased exponentially by 90.7% until it reached a steady-state level of 1.70 mN mm{sup -1}. (communication)

  7. Arterial Stiffness in Nonhypertensive Type 2 Diabetes Patients in Ghana

    Directory of Open Access Journals (Sweden)

    Kwame Yeboah

    2016-01-01

    Full Text Available Background. Increased arterial stiffness is an independent cardiovascular risk factor in diabetes patients and general population. However, the contribution of diabetes to arterial stiffness is often masked by coexistent obesity and hypertension. In this study, we assessed arterial stiffness in nonhypertensive, nonobese type 2 diabetes (T2DM patients in Ghana. Methods. In case-control design, 166 nonhypertensive, nonobese participants, comprising 96 T2DM patients and 70 nondiabetes controls, were recruited. Peripheral and central blood pressure (BP indices were measured, and arterial stiffness was assessed as aortic pulse wave velocity (PWVao, augmentation index (AIx, cardioankle vascular index (CAVI, and heart-ankle pulse wave velocity (haPWV. Results. With similar peripheral and central BP indices, T2DM patients had higher PWVao (8.3 ± 1 versus 7.8 ± 1.3, p=0.044 and CAVI (7.9 ± 1.2 versus 6.9 ± 0.7, p=0.021 than nondiabetic control. AIx and haPWV were similar between T2DM and nondiabetic controls. Multiple regression models showed that, in the entire study participants, the major determinants of PWVao were diabetes status, age, gender, systolic BP, and previous smoking status (β = 0.22, 0.36, 0.48, 0.21, and 0.25, resp.; all p<0.05; the determinants of CAVI were diabetes status, age, BMI, heart rate, HbA1c, total cholesterol, HDL cholesterol, and previous smoking status (β = 0.21, 0.38, 0.2, 0.18, 0.24. 0.2, −0.19, and 0.2, resp.; all p<0.05. Conclusion. Our findings suggest that nonhypertensive, nonobese T2DM patients have increased arterial stiffness without appreciable increase in peripheral and central pressure indices.

  8. Aortic valve replacement for aortic stenosis caused by alkaptonuria.

    Science.gov (United States)

    Hiroyoshi, Junko; Saito, Aya; Panthee, Nirmal; Imai, Yasushi; Kawashima, Dai; Motomura, Noboru; Ono, Minoru

    2013-03-01

    We report a case of aortic stenosis associated with ochronosis in a 70-year-old man who underwent biologic aortic valve replacement. Intraoperative findings included ochronosis of a severely calcified pigmented aortic valve along with pigmentation of the intima of the aorta. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  9. Surgical repair of a celiac artery aneurysm using a sutureless proximal anastomosis device

    Directory of Open Access Journals (Sweden)

    Tetsuro Uchida, MD, PhD

    2017-12-01

    Full Text Available Some celiac artery aneurysms are not suitable for endovascular therapy. We describe the case of a 63-year-old man with a celiac trunk aneurysm extending to the hepatosplenic bifurcation. The aneurysm was resected and oversewn at the origin from the abdominal aorta. A saphenous vein bypass from the supraceliac aorta to the celiac artery bifurcation was performed using a sutureless anastomotic device (PAS-Port system; Cardica, Redwood City, Calif to create the proximal anastomosis, eliminating the need for aortic clamping. This system is thought to make direct proximal aortic anastomosis safe and easy in patients requiring surgical reconstruction of celiac artery aneurysms.

  10. Pathogenetic Basis of Aortopathy and Aortic Valve Disease

    Science.gov (United States)

    2018-02-19

    Aortopathies; Thoracic Aortic Aneurysm; Aortic Valve Disease; Thoracic Aortic Disease; Thoracic Aortic Dissection; Thoracic Aortic Rupture; Ascending Aortic Disease; Descending Aortic Disease; Ascending Aortic Aneurysm; Descending Aortic Aneurysm; Marfan Syndrome; Loeys-Dietz Syndrome; Ehlers-Danlos Syndrome; Shprintzen-Goldberg Syndrome; Turner Syndrome; PHACE Syndrome; Autosomal Recessive Cutis Laxa; Congenital Contractural Arachnodactyly; Arterial Tortuosity Syndrome

  11. Coronary ostial involvement in acute aortic dissection: detection with 64-slice cardiac CT.

    LENUS (Irish Health Repository)

    Ryan, E Ronan

    2012-02-01

    A 41-year-old man collapsed after lifting weights at a gym. Following admission to the emergency department, a 64-slice cardiac computed tomography (CT) revealed a Stanford Type A aortic dissection arising from a previous coarctation repair. Multiphasic reconstructions demonstrated an unstable, highly mobile aortic dissection flap that extended proximally to involve the right coronary artery ostium. Our case is an example of the application of electrocardiogram-gated cardiac CT in directly visualizing involvement of the coronary ostia in acute aortic dissection, which may influence surgical management.

  12. Endograft Collapse After Endovascular Treatment for Thoracic Aortic Disease

    International Nuclear Information System (INIS)

    Bandorski, Dirk; Brueck, Martin; Guenther, Hans-Ulrich; Manke, Christoph

    2010-01-01

    Endovascular treatment is an established therapy for thoracic aortic disease. Collapse of the endograft is a potentially fatal complication. We reviewed 16 patients with a thoracic endograft between 2001 and 2006. Medical records of the treated patients were studied. Data collected include age, gender, diagnosis, indication for endoluminal treatment, type of endograft, and time of follow up. All patients (n = 16; mean age, 61 years; range, 21-82 years) underwent computed tomography (CT) for location of the lesion and planning of the intervention. Time of follow-up with CT scan ranged from 1 to 61 months. Indications for endovascular treatment were degenerative aneurysm (n = 7; 44%), aortic dissection (n = 2; 12%), perforated aortic ulcer (n = 4; 25%), and traumatic aortic injury (n = 3; 19%). Three patients suffered from a collapse of the endograft (one patient distal, two patients proximal) between 3 and 8 days after endovascular treatment. These patients were younger (mean age, 37 ± 25 years vs. 67 ± 16 years; P 0.05]; distal, 45 ± 23.5% vs. 38 ± 21.7% [P > 0.05]). Proximal collapse was corrected by placing a bare stent. In conclusion, risk factors for stent-graft collapse are a small lumen of the aorta and a small radius of the aortic arch curvature (young patients), as well as oversizing, which is an important risk factor and is described for different types of endografts and protheses (Gore TAG and Cook Zenith). Dilatation of the collapsed stent-graft is not sufficient. Following therapy implantation of a second stent or surgery is necessary in patients with a proximal endograft collapse. Distal endograft collapse can possibly be treated conservatively under close follow-up.

  13. Acupuncture therapy improves vascular hemodynamics and stiffness in middle-age hypertensive individuals.

    Science.gov (United States)

    Terenteva, Nina; Chernykh, Oksana; Sanchez-Gonzalez, Marcos A; Wong, Alexei

    2018-02-01

    Acupuncture (ACU) is becoming a more common practice among hypertensive individuals. However, the reported therapeutic effects of ACU in lowering brachial blood pressure (BP) are ambiguous. Therefore, evaluating more sensitive markers of arterial functioning might unveil the protective effects of ACU on hypertension. We examined the effects of an 8-week ACU therapy intervention on vascular hemodynamics and stiffness in middle-age hypertensive individuals. Participants were randomly assigned to either ACU (n = 23) or a control group (n = 22). Brachial and aortic BP, wave reflection (AIx) and arterial stiffness (SI) were measured before and after 8 weeks. There was a significant group x time interaction (P < 0.05) for brachial and aortic BP, AIx and SI which significantly decreased (P < 0.05) following ACU but not after control. ACU led to reductions in brachial and aortic BP, wave reflection and arterial stiffness in middle-age hypertensive individuals. ACU might be effective in the prevention and treatment of hypertension. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Early Results of Chimney Technique for Type B Aortic Dissections Extending to the Aortic Arch

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chen [Affiliated Hospital of Nantong University, Department of General Surgery (China); Tang, Hanfei; Qiao, Tong; Liu, Changjian; Zhou, Min, E-mail: 813477618@qq.com [The Affiliated Hospital of Nanjing University Medical School, Department of Vascular Surgery, Nanjing Drum Tower Hospital (China)

    2016-01-15

    ObjectiveTo summarize our early experience gained from the chimney technique for type B aortic dissection (TBAD) extending to the aortic arch and to evaluate the aortic remodeling in the follow-up period.MethodsFrom September 2011 to July 2014, 27 consecutive TBAD patients without adequate proximal landing zones were retrograde analyzed. Chimney stent-grafts were deployed parallel to the main endografts to reserve flow to branch vessels while extending the landing zones. In the follow-up period, aortic remodeling was observed with computed tomography angiography.ResultsThe technical success rate was 100 %, and endografts were deployed in zone 0 (n = 3, 11.1 %), zone 1 (n = 18, 66.7 %), and zone 2 (n = 6, 22.2 %). Immediately, proximal endoleaks were detected in 5 patients (18.5 %). During a mean follow-up period of 17.6 months, computed tomography angiography showed all the aortic stent-grafts and chimney grafts to be patent. Favorable remodeling was observed at the level of maximum descending aorta and left subclavian artery with expansion of true lumen (from 18.4 ± 4.8 to 25 ± 0.86 mm, p < 0.001 and 27.1 ± 0.62 to 28.5 ± 0.37 mm, p < 0.001) and depressurization of false lumen (from 23.7 ± 2.7 to 8.7 ± 3.8 mm, p < 0.001, from 5.3 ± 1.2 to 2.1 ± 2.1 mm, p < 0.001). While at the level of maximum abdominal aorta, suboptimal remodeling of the total aorta (from 24.1 ± 0.4 to 23.6 ± 1.5 mm, p = 0.06) and true lumen (from 13.8 ± 0.6 to 14.5 ± 0.4 mm, p = 0.08) was observed.ConclusionBased on our limited experience, the chimney technique with thoracic endovascular repair is demonstrated to be promising for TBAD extending to the arch with favorable aortic remodeling.

  15. Robotic aortic surgery.

    Science.gov (United States)

    Duran, Cassidy; Kashef, Elika; El-Sayed, Hosam F; Bismuth, Jean

    2011-01-01

    Surgical robotics was first utilized to facilitate neurosurgical biopsies in 1985, and it has since found application in orthopedics, urology, gynecology, and cardiothoracic, general, and vascular surgery. Surgical assistance systems provide intelligent, versatile tools that augment the physician's ability to treat patients by eliminating hand tremor and enabling dexterous operation inside the patient's body. Surgical robotics systems have enabled surgeons to treat otherwise untreatable conditions while also reducing morbidity and error rates, shortening operative times, reducing radiation exposure, and improving overall workflow. These capabilities have begun to be realized in two important realms of aortic vascular surgery, namely, flexible robotics for exclusion of complex aortic aneurysms using branched endografts, and robot-assisted laparoscopic aortic surgery for occlusive and aneurysmal disease.

  16. Aortic valve replacement

    DEFF Research Database (Denmark)

    Kapetanakis, Emmanouil I; Athanasiou, Thanos; Mestres, Carlos A

    2008-01-01

    mortality were collected. Group analysis by patient geographic distribution and by annular diameter of the prosthesis utilized was conducted. Patients with a manufacturer's labeled prosthesis size > or = 21 mm were assigned to the 'large' aortic size subset, while those with a prosthesis size ... differences in the distribution of either gender or BSA. In the multivariable model, south European patients were seven times more likely to receive a smaller-sized aortic valve (OR = 6.5, 95% CI = 4.82-8.83, p

  17. Measurement and Treatment of Passive Muscle Stiffness

    DEFF Research Database (Denmark)

    Kirk, Henrik

    , which aimed to investigate: 1) The development of a clinical method to evaluate and distinguish neural (reflex mediated stiffness) and non-neural (passive muscle stiffness) components of muscle stiffness in adults with CP by objective and reliable measurements. 2) The association between increased...... and reliability of the method, and argue for the use of the method in the clinical practice. The device is able to distinguish between passive muscle stiffness and reflex-mediated stiffness in subjects with CP. It shows good high intrarater and interrater reliability in evaluation of passive muscle stiffness...... to measure muscle stiffness, and distinguish between passive muscle stiffness and reflex-mediated stiffness. Furthermore, it is a reliable device to measure changes in passive ROM. Treatment of passive muscle stiffness should be directed towards intense training, comprising many repetitions with a functional...

  18. Double aortic arch

    Science.gov (United States)

    Surgery can be done to fix double aortic arch. The surgeon ties off the smaller branch and separates it from the larger branch. Then the surgeon closes the ends of the aorta with stitches. This relieves pressure on the esophagus and windpipe.

  19. Bicuspid aortic valve

    Science.gov (United States)

    ... aortic disease. In: Otto CM, Bonow RO, eds. Valvular Heart Disease: A Companion to Braunwald’s Heart Disease . 4th ed. ... PA: Elsevier Saunders; 2014:chap 13. Carabello BA. Valvular heart disease. In: Goldman L, Schafer AI, eds. Goldman’s Cecil ...

  20. Aortic Valve Stenosis

    Science.gov (United States)

    ... most cases, doctors don't know why a heart valve fails to develop properly, so it isn't something you could have prevented. Calcium buildup on the valve. With age, heart valves may accumulate deposits of calcium (aortic valve ...

  1. Acute changes in arterial stiffness following exercise in people with metabolic syndrome.

    Science.gov (United States)

    Radhakrishnan, Jeyasundar; Swaminathan, Narasimman; Pereira, Natasha M; Henderson, Keiran; Brodie, David A

    This study aims to examine the changes in arterial stiffness immediately following sub-maximal exercise in people with metabolic syndrome. Ninety-four adult participants (19-80 years) with metabolic syndrome gave written consent and were measured for arterial stiffness using a SphygmoCor (SCOR-PVx, Version 8.0, Atcor Medical Private Ltd, USA) immediately before and within 5-10min after an incremental shuttle walk test. The arterial stiffness measures used were pulse wave velocity (PWV), aortic pulse pressure (PP), augmentation pressure, augmentation index (AI), subendocardial viability ratio (SEVR) and ejection duration (ED). There was a significant increase (pexercise. Exercise capacity had a strong inverse correlation with arterial stiffness and age (pExercise capacity is inversely related to arterial stiffness and age in people with metabolic syndrome. Exercise induced changes in arterial stiffness measured using pulse wave analysis is an important tool that provides further evidence in studying cardiovascular risk in metabolic syndrome. Copyright © 2016 Diabetes India. Published by Elsevier Ltd. All rights reserved.

  2. Arterial stiffness, central hemodynamics, and cardiovascular risk in hypertension

    Science.gov (United States)

    Palatini, Paolo; Casiglia, Edoardo; Gąsowski, Jerzy; Głuszek, Jerzy; Jankowski, Piotr; Narkiewicz, Krzysztof; Saladini, Francesca; Stolarz-Skrzypek, Katarzyna; Tikhonoff, Valérie; Van Bortel, Luc; Wojciechowska, Wiktoria; Kawecka-Jaszcz, Kalina

    2011-01-01

    This review summarizes several scientific contributions at the recent Satellite Symposium of the European Society of Hypertension, held in Milan, Italy. Arterial stiffening and its hemodynamic consequences can be easily and reliably measured using a range of noninvasive techniques. However, like blood pressure (BP) measurements, arterial stiffness should be measured carefully under standardized patient conditions. Carotid-femoral pulse wave velocity has been proposed as the gold standard for arterial stiffness measurement and is a well recognized predictor of adverse cardiovascular outcome. Systolic BP and pulse pressure in the ascending aorta may be lower than pressures measured in the upper limb, especially in young individuals. A number of studies suggest closer correlation of end-organ damage with central BP than with peripheral BP, and central BP may provide additional prognostic information regarding cardiovascular risk. Moreover, BP-lowering drugs can have differential effects on central aortic pressures and hemodynamics compared with brachial BP. This may explain the greater beneficial effect provided by newer antihypertensive drugs beyond peripheral BP reduction. Although many methodological problems still hinder the wide clinical application of parameters of arterial stiffness, these will likely contribute to cardiovascular assessment and management in future clinical practice. Each of the abovementioned parameters reflects a different characteristic of the atherosclerotic process, involving functional and/or morphological changes in the vessel wall. Therefore, acquiring simultaneous measurements of different parameters of vascular function and structure could theoretically enhance the power to improve risk stratification. Continuous technological effort is necessary to refine our methods of investigation in order to detect early arterial abnormalities. Arterial stiffness and its consequences represent the great challenge of the twenty-first century for

  3. Effects of Different Exercise Modes on Arterial Stiffness and Nitric Oxide Synthesis.

    Science.gov (United States)

    Hasegawa, Natsuki; Fujie, Shumpei; Horii, Naoki; Miyamoto-Mikami, Eri; Tsuji, Katsunori; Uchida, Masataka; Hamaoka, Takafumi; Tabata, Izumi; Iemitsu, Motoyuki

    2018-06-01

    Aerobic training (AT) and high-intensity intermittent training (HIIT) reduce arterial stiffness, whereas resistance training (RT) induces deterioration of or no change in arterial stiffness. However, the molecular mechanism of these effects of different exercise modes remains unclear. This study aimed to clarify the difference of different exercise effects on endothelial nitric oxide synthase (eNOS) signaling pathway and arterial stiffness in rats and humans. In the animal study, forty 10-wk-old male Sprague-Dawley rats were randomly divided into four groups: sedentary control (CON), AT (treadmill running, 60 min at 30 m·min, 5 d·wk for 8 wk), RT (ladder climbing, 8-10 sets per day, 3 d·wk for 8 wk), and HIIT (14 repeats of 20-s swimming session with 10-s pause between sessions, 4 d·wk for 6 wk from 12-wk-old) groups (n = 10 in each group). In the human study, we confirmed the effects of 6-wk HIIT and 8-wk AT interventions on central arterial stiffness and plasma nitrite/nitrate level in untrained healthy young men in randomized controlled trial (HIIT, AT, and CON; n = 7 in each group). In the animal study, the effect on aortic pulse wave velocity (PWV), as an index of central arterial stiffness, after HIIT was the same as the decrease in aortic PWV and increase in arterial eNOS/Akt phosphorylation after AT, which was not changed by RT. A negative correlation between aortic PWV and eNOS phosphorylation was observed (r = -0.38, P HIIT- and AT-induced changes in carotid-femoral PWV (HIIT -115.3 ± 63.4 and AT -157.7 ± 45.7 vs CON 71.3 ± 61.1 m·s, each P HIIT may reduce central arterial stiffness via the increase in aortic nitric oxide bioavailability despite it being done in a short time and short term and has the same effects as AT.

  4. Impact of Aortic Insufficiency on Ascending Aortic Dilatation and Adverse Aortic Events After Isolated Aortic Valve Replacement in Patients With a Bicuspid Aortic Valve.

    Science.gov (United States)

    Wang, Yongshi; Wu, Boting; Li, Jun; Dong, Lili; Wang, Chunsheng; Shu, Xianhong

    2016-05-01

    Aberrant flow pattern and congenital fragility bestows bicuspid aortic valve (BAV) with a propensity toward ascending aorta dilatation, aneurysm, and dissection. Whether isolated aortic valve replacement (AVR) can prevent further dilatation in BAV ascending aorta and what indicates concurrent aortic intervention in the case of valve operation remain controversial. From June 2006 to January 2009, patients with a BAV who underwent isolated AVR were consecutively included and categorized into aortic insufficiency (BAV-AI, n = 84) and aortic stenosis (n = 112) groups, and another population of patients with a tricuspid aortic valve with aortic insufficiency (n = 149) was also recruited during the same period for comparison of annual aortic dilatation rate and adverse aortic events after isolated AVR. With a median follow-up period of 72 months (interquartile range, 66 to 78 months), ascending aorta dilatation rates were faster in the BAV-AI group than the BAV plus aortic stenosis and tricuspid aortic valve with aortic insufficiency groups (both p regression analysis identified aortic insufficiency (hazard ratio, 3.7; 95% confidence interval, 1.2 to 11.1; p = 0.019) as an independent risk factor for adverse aortic events among patients with BAV in general, whereas preoperative ascending aortic diameter larger than 45 mm (hazard ratio, 13.8; 95% confidence interval, 3.0 to 63.3; p = 0.001) served as a prognostic indicator in the BAV-AI group. An aggressive policy of preventive aortic interventions seemed appropriate in patients with BAV-AI during AVR, and BAV phenotype presenting as either insufficiency or stenosis should be taken into consideration when contemplating optimal surgical strategies for BAV aortopathy. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  5. Evolution of the Proximal Sealing Rings of the Anaconda Stent-Graft After Endovascular Aneurysm Repair

    NARCIS (Netherlands)

    Koenrades, Maaike A.; Klein, Almar; Leferink, Anne M.; Slump, Cornelis H.; Geelkerken, Robert H.

    2018-01-01

    Purpose: To provide insight into the evolution of the saddle-shaped proximal sealing rings of the Anaconda stent-graft after endovascular aneurysm repair (EVAR). Methods: Eighteen abdominal aortic aneurysm patients were consecutively enrolled in a single-center, prospective, observational cohort

  6. Association of Gastrocnemius Muscle Stiffness With Passive Ankle Joint Stiffness and Sex-Related Difference in the Joint Stiffness.

    Science.gov (United States)

    Chino, Kintaro; Takashi, Hideyuki

    2017-11-15

    Passive ankle joint stiffness is affected by all structures located within and over the joint, and is greater in men than in women. Localized muscle stiffness can be assessed by ultrasound shear wave elastography, and muscle architecture such as fascicle length and pennation angle can be measured by B-mode ultrasonography. Thus, we assessed localized muscle stiffness of the medial gastrocnemius (MG) with consideration of individual variability in the muscle architecture, and examined the association of the muscle stiffness with passive ankle joint stiffness and the sex-related difference in the joint stiffness. Localized muscle stiffness of the MG in 16 men and 17 women was assessed at 10° and 20° plantar flexion, neutral anatomical position, 10° and 20° dorsiflexion. Fascicle length and pennation angle of the MG were measured at these joint positions. Passive ankle joint stiffness was determined by the ankle joint angle-torque relationship. Localized MG muscle stiffness was not significantly correlated with passive ankle joint stiffness, and did not show significant sex-related difference, even when considering the muscle architecture. This finding suggest that muscle stiffness of the MG would not be a prominent factor to determine passive ankle joint stiffness and the sex-related difference in the joint stiffness.

  7. Acute Aortic Arch Perforation During Transcatheter Aortic Valve Replacement in Bicuspid Aortic Stenosis and a Gothic Aortic Arch.

    Science.gov (United States)

    Millan-Iturbe, Oscar; Sawaya, Fadi J; Bieliauskas, Gintautas; Chow, Danny H F; De Backer, Ole; Søndergaard, Lars

    2017-09-01

    Transcatheter aortic valve replacement (TAVR) has evolved from a novel technology to an established therapy for high/intermediate-risk patients with severe symptomatic aortic stenosis (AS). Although TAVR is used to treat bicuspid severe AS, the large randomized trials typically excluded bicuspid AS because of its unique anatomic features. This case report describes an acute aortic perforation during delivery of a transcatheter heart valve to treat a severe bicuspid AS with a "gothic aortic arch"; more careful evaluation of the preprocedural multislice computed tomographic scan would have unveiled a sharply angulated aortic arch. This life-threatening complication was successfully treated by thoracic endovascular aortic repair. Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  8. Neighborhoods and manageable proximity

    Directory of Open Access Journals (Sweden)

    Stavros Stavrides

    2011-08-01

    Full Text Available The theatricality of urban encounters is above all a theatricality of distances which allow for the encounter. The absolute “strangeness” of the crowd (Simmel 1997: 74 expressed, in its purest form, in the absolute proximity of a crowded subway train, does not generally allow for any movements of approach, but only for nervous hostile reactions and submissive hypnotic gestures. Neither forced intersections in the course of pedestrians or vehicles, nor the instantaneous crossing of distances by the technology of live broadcasting and remote control give birth to places of encounter. In the forced proximity of the metropolitan crowd which haunted the city of the 19th and 20th century, as well as in the forced proximity of the tele-presence which haunts the dystopic prospect of the future “omnipolis” (Virilio 1997: 74, the necessary distance, which is the stage of an encounter between different instances of otherness, is dissipated.

  9. Abdominal Aortic Aneurysm

    Science.gov (United States)

    ... AAAs don’t cause symptoms unless they leak, tear, or rupture. If this happens, you may experience: sudden pain in your abdomen, groin, back, legs, or buttocks nausea and vomiting abnormal stiffness in your abdominal muscles problems with urination or bowel movements clammy, sweaty ...

  10. Neonatal aortic stenosis.

    Science.gov (United States)

    Drury, Nigel E; Veldtman, Gruschen R; Benson, Lee N

    2005-09-01

    Neonatal aortic stenosis is a complex and heterogeneous condition, defined as left ventricular outflow tract obstruction at valvular level, presenting and often requiring treatment in the first month of life. Initial presentation may be catastrophic, necessitating hemodynamic, respiratory and metabolic resuscitation. Subsequent management is focused on maintaining systemic blood flow, either via a univentricular Norwood palliation or a biventricular route, in which the effective aortic valve area is increased by balloon dilation or surgical valvotomy. In infants with aortic annular hypoplasia but adequately sized left ventricle, the Ross-Konno procedure is also an attractive option. Outcomes after biventricular management have improved in recent years as a consequence of better patient selection, perioperative management and advances in catheter technology. Exciting new developments are likely to significantly modify the natural history of this disorder, including fetal intervention for the salvage of the hypoplastic left ventricle; 3D echocardiography providing better definition of valve morphology and aiding patient selection for a surgical or catheter-based intervention; and new transcutaneous approaches, such as duel beam echo, to perforate the valve.

  11. Cadaveric aorta implantation for aortic graft infection.

    Science.gov (United States)

    Ali, Asad; Bahia, Sandeep S S; Ali, Tahir

    2016-01-01

    This case report describes a 73-year-old gentleman who underwent explantation of an infected prosthetic aorto-iliac graft and replacement with a cryopreserved thoracic and aorto-iliac allograft. The patient has been followed up a for more than a year after surgery and remains well. After elective tube graft repair of his abdominal aortic aneurysm (AAA) in 2003, he presented to our unit in 2012 in cardiac arrest as a result of a rupture of the distal graft suture line due to infection. After resuscitation he underwent aorto-bifemoral grafting using a cuff of the original aortic graft proximally. Distally the new graft was anastomosed to his common femoral arteries, with gentamicin beads left in situ. Post discharge the patient was kept under close surveillance with serial investigations including nuclear scanning, however it became apparent that his new graft was infected and that he would require aortic graft replacement, an operation with a mortality of at least 50%. The patient underwent the operation and findings confirmed a synthetic graft infection. This tube graft was explanted and a cryopreserved aorta was used to the refashion the abdominal aorta and its bifurcation. The operation required a return to theatre day one post operatively for a bleeding side branch, which was repaired. The patient went on to make a full recovery stepping down from the intensive therapy unit day 6 post operatively and went on to be discharged 32 days after his cryopreserved aorta implantation. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  12. Right circumflex retro-oesophageal aortic arch with coarctation of a high-positioned right arch

    International Nuclear Information System (INIS)

    Ahn, Kyung-Sik; Yong, Hwan Seok; Woo, Ok Hee; Kang, Eun-Young; Lee, Joo-Won

    2007-01-01

    We present a rare case of right circumflex retro-oesophageal aortic arch with coarctation of a high-positioned right arch. A 7-month-old boy presented with a cardiac murmur. Cardiac situs was normal and there was no evidence of an intracardiac shunt or patent ductus arteriosus. MR aortography revealed a right aortic arch that was high-positioned, tortuous and narrowed. This right aortic arch crossed the midline behind the oesophagus and continued as a left-sided descending aorta. The left common carotid and subclavian arteries arose from a large branching vascular structure that derived from the top of the left-sided descending aorta. The right common carotid artery arose from the ascending aorta. The proximal portion of the right common carotid artery showed very severe stenosis and poststenotic dilatation. The right subclavian artery originated distal to the narrowed and tortuous segment of the aortic arch. (orig.)

  13. Development of stroke-induced quadriplegia after endovascular repair of blunt aortic injury pseudoaneurysm.

    Science.gov (United States)

    Amoudi, Abdullah S; Merdad, Anas A; Makhdoom, Ahmed Q; Jamjoom, Reda A

    2015-01-01

    Endovascular repair of blunt aortic injury is now a first-line approach in management. This can warrant coverage of the left subclavian artery (LSA), which could lead to posterior strokes. In this case report, we present a severe complication of endovascular repair of a traumatic aortic aneurysm. A 53-year-old man presented with blunt aortic injury, endovascular repair was carried out where the left subclavian artery was covered. The intervention had a 100% technical success. Twelve hours later, he was discovered to have quadriplegia, a CT scan showed a large left cerebellar infarction extending to the medulla oblongata and proximal spinal cord. Strokes complicate 3% of thoracic endovascular aortic repairs, 80% of those strokes occur in patients who had their LSA`s covered. Most patients however, tolerate the coverage. Although our patient had a dominant right vertebral artery, and lacked risks for these strokes, he developed an extensive stroke that left him quadriplegic.

  14. Endovascular repair of traumatic thoracic aortic tears.

    Science.gov (United States)

    Mansour, M Ashraf; Kirk, Jeffrey S; Cuff, Robert F; Banegas, Shonda L; Ambrosi, Gavin M; Liao, Timothy H; Chambers, Christopher M; Wong, Peter Y; Heiser, John C

    2012-03-01

    Patients with thoracic aorta injuries (TAI) present a unique challenge. The purpose of this study was to review the outcomes of thoracic endovascular aortic repair (TEVAR) in patients with TAI. A retrospective chart review of all patients admitted for TEVAR for trauma was performed. In a 5-year period, 19 patients (6 women and 13 men; average age, 42 y) were admitted to our trauma center with TAI. Mechanism of injury was a motor vehicle crash in 12 patients, motorcycle crash in 2 patients, automobile-pedestrian accident in 2 patients, 1 fall, 1 crush injury, and 1 stab wound to the back. A thoracic endograft was used in 6 patients and proximal aortic cuffs were used in 13 patients (68%). One patient (5%) died. There were no strokes, myocardial infarctions, paraplegia, or renal failure. TEVAR for TAI appears to be a safe option for patients with multiple injuries. TEVAR in young patients is still controversial because long-term endograft behavior is unknown. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. 5B.05: MARFAN SYNDROME: ASSESSMENT OF AORTIC DISSECTION RISK BY ANALYSIS OF AORTIC VISCOELASTIC PROPERTIES.

    Science.gov (United States)

    Grillo, A; Pini, A; Marelli, S; Gan, L; Giuliano, A; Trifirò, G; Santini, F; Salvi, L; Salvi, P; Viecca, F; Carretta, R; Parati, G

    2015-06-01

    Marfan syndrome is an autosomal dominant genetic disorder characterized by an abnormal fibrillin-1 synthesis. Aortic root dilation and dissection are the main problems affecting patients prognosis in these patients. Their pharmacological prophylaxis with losartan or with a beta-blocker counteracts the aortic root dilation, but a close follow-up is required to assess therapeutic response rate and to identify non-responders. Unfortunately genotype-phenotype studies do not allow to determine the exact risk profile in these patients and there is no reliable method to accurately predict their risk of aortic dissection. Aim of this study was to evaluate non-invasive markers for identification of Marfan patients at higher risk of aortic complications. We studied 187 Marfan patients (identified according to 2010 Revised Ghent Criteria and positive genetic analysis), age 32.3 ± 16.5 yrs (mean ± SD). 52 patients (27.8%) had undergone surgical ascending aorta replacement (David or Bentall procedure). Central pressure curves were recorded by PulsePen tonometer, and the aortic viscoelastic aortic properties were studied by determination of carotid-femoral pulse wave velocity (PWV). With reference to the age related distribution of PWV values in a normal population, defined according to Arterial-Stiffness-Collaboration, PWV mean values in Marfan patients corresponded to 60th percentile in non- operated patients and to the 67th percentile in those operated. Adult Marfan patients (n = 146) generally displayed a low blood pressure, because of the pharmacological prophylaxis, and were compared with a population of 189 adult healthy subjects (81 males), matched by age (38 ± 13 vs 38 ± 16 yrs.), heart rate (64 ± 9 bpm vs 64 ± 11 bpm) and blood pressure (mean BP = 78 ± 9 mmHg vs 79 ± 4 mmHg) values. Average PWV value was higher than in healthy controls (PWV = 7.0 ± 1.7) both in not operated (PWV = 7.6 ± 1.6; p = 0

  16. Properties and determination of the interface stiffness

    International Nuclear Information System (INIS)

    Du Danxu; Zhang Hao; Srolovitz, David J.

    2007-01-01

    The chemical potential of a curved interface contains a term that is proportional to the product of the interface curvature and the interface stiffness. In crystalline materials, the interface stiffness is a tensor. This paper examines several basic issues related to the properties of the interface stiffness, especially the determination of the interface stiffness in particular directions (i.e. the commonly used scalar form of the interface stiffness). Of the five parameters that describe an arbitrary grain boundary, only those describing the inclination are crucial for the scalar stiffness. We also examine the influence of crystal symmetry on the stiffness tensor for both free surfaces and grain boundaries. This results in substantial simplifications for cases in which interfaces possess mirror or rotational symmetries. An efficient method for determining the interface stiffness tensor using atomistic simulations is proposed

  17. Proximal collagenous gastroenteritides:

    DEFF Research Database (Denmark)

    Nielsen, Ole Haagen; Riis, Lene Buhl; Danese, Silvio

    2014-01-01

    AIM: While collagenous colitis represents the most common form of the collagenous gastroenteritides, the collagenous entities affecting the proximal part of the gastrointestinal tract are much less recognized and possibly overlooked. The aim was to summarize the latest information through a syste...

  18. Proximal femoral fractures

    DEFF Research Database (Denmark)

    Palm, Henrik; Teixidor, Jordi

    2015-01-01

    searched the homepages of the national heath authorities and national orthopedic societies in West Europe and found 11 national or regional (in case of no national) guidelines including any type of proximal femoral fracture surgery. RESULTS: Pathway consensus is outspread (internal fixation for un...

  19. Proximate Analysis of Coal

    Science.gov (United States)

    Donahue, Craig J.; Rais, Elizabeth A.

    2009-01-01

    This lab experiment illustrates the use of thermogravimetric analysis (TGA) to perform proximate analysis on a series of coal samples of different rank. Peat and coke are also examined. A total of four exercises are described. These are dry exercises as students interpret previously recorded scans. The weight percent moisture, volatile matter,…

  20. Hybrid endovascular treatment of an aortic root and thoracoabdominal aneurysm in a high-risk patient with Marfan syndrome.

    Science.gov (United States)

    Gelpi, Guido; Mazzaccaro, Daniela; Romagnoni, Claudia; Contino, Monica; Antona, Carlo

    2013-05-01

    This report describes the hybrid endovascular treatment of an aortic root dilatation and a thoracoabdominal aneurysm in a high-risk patient with Marfan syndrome. A 50-year-old male, in hemodialysis for polycystic kidney and polycystic liver, was referred to our department for aortic root dilatation of 5 cm and a 6.3-cm thoracoabdominal aneurysm . He already underwent surgical repair of abdominal aortic aneurysm 10 years ago, complicated by pseudoaneurysm of the proximal anastomosis that had been treated in another center, with an endoprosthesis. The patient underwent aortic root replacement, aortic valve sparing operation, and rerouting of the superior mesenteric artery and celiac trunk to the ascending aorta. The thoracoabdominal aneurysm was excluded with an endoprosthesis few days after the surgical step. The 12-month computed tomography scan confirmed the complete exclusion of the thoracoabdominal aneurysm.

  1. Impact of aortic root size on left ventricular afterload and stroke volume.

    Science.gov (United States)

    Sahlén, Anders; Hamid, Nadira; Amanullah, Mohammed Rizwan; Fam, Jiang Ming; Yeo, Khung Keong; Lau, Yee How; Lam, Carolyn S P; Ding, Zee Pin

    2016-07-01

    The left ventricle (LV) ejects blood into the proximal aorta. Age and hypertension are associated with stiffening and dilation of the aortic root, typically viewed as indicative of adverse remodeling. Based on analytical considerations, we hypothesized that a larger aortic root should be associated with lower global afterload (effective arterial elastance, EA) and larger stroke volume (SV). Moreover, as antihypertensive drugs differ in their effect on central blood pressure, we examined the role of antihypertensive drugs for the relation between aortic root size and afterload. We studied a large group of patients (n = 1250; 61 ± 12 years; 78 % males; 64 % hypertensives) from a single-center registry with known or suspected coronary artery disease. Aortic root size was measured by echocardiography as the diameter of the tubular portion of the ascending aorta. LV outflow tract Doppler was used to record SV. In the population as a whole, after adjusting for key covariates in separate regression models, aortic root size was an independent determinant of both SV and EA. This association was found to be heterogeneous and stronger in patients taking a calcium channel blocker (CCB; 10.6 % of entire population; aortic root size accounted for 8 % of the explained variance of EA). Larger aortic root size is an independent determinant of EA and SV. This association was heterogeneous and stronger in patients on CCB therapy.

  2. Shoulder Stiffness : Current Concepts and Concerns

    NARCIS (Netherlands)

    Itoi, Eiji; Arce, Guillermo; Bain, Gregory I.; Diercks, Ronald L.; Guttmann, Dan; Imhoff, Andreas B.; Mazzocca, Augustus D.; Sugaya, Hiroyuki; Yoo, Yon-Sik

    Shoulder stiffness can be caused by various etiologies such as immobilization, trauma, or surgical interventions. The Upper Extremity Committee of ISAKOS defined the term "frozen shoulder" as idiopathic stiff shoulder, that is, without a known cause. Secondary stiff shoulder is a term that should be

  3. Normal values of aortic dimensions, distensibility, and pulse wave velocity in children and young adults: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Voges Inga

    2012-11-01

    Full Text Available Abstract Background Aortic enlargement and impaired bioelasticity are of interest in several cardiac and non-cardiac diseases as they can lead to cardiovascular complications. Cardiovascular magnetic resonance (CMR is increasingly accepted as a noninvasive tool in cardiovascular evaluation. Assessment of aortic anatomy and bioelasticity, namely aortic distensibility and pulse wave velocity (PWV, by CMR is accurate and reproducible and could help to identify anatomical and bioelastic abnormalities of the aorta. However, normal CMR values for healthy children and young adults are lacking. Methods Seventy-one heart-healthy subjects (age 16.4 ± 7.6 years, range 2.3 - 28.3 years were examined using a 3.0 Tesla CMR scanner. Aortic cross-sectional areas and aortic distensibility were measured at four positions of the ascending and descending thoracic aorta. PWV was assessed from aortic blood flow velocity measurements in a aortic segment between the ascending aorta and the proximal descending aorta. The Lambda-Mu-Sigma (LMS method was used to obtain percentile curves for aortic cross-sectional areas, aortic distensibility and PWV according to age. Results Aortic areas, PWV and aortic distensibility (aortic cross-sectional areas: r = 0.8 to 0.9, p  Conclusions This study provides percentile curves for cross-sectional areas, distensibility and pulse wave velocity of the thoracic aorta in children and young adolescents between their 3rd and 29th year of life. These data may serve as a reference for the detection of pathological changes of the aorta in cardiovascular disease.

  4. Aortic obstruction: anatomy and echocardiography

    Directory of Open Access Journals (Sweden)

    Keirns Candace

    2006-09-01

    Full Text Available Abstract Echocardiography is a valuable non-invasive technique for identifying the site and type of aortic obstruction. Knowledge of the morphological details of each type of obstruction is the basis for correct interpretation of the diagnostic images and clinical decisions. This study was undertaken to correlate the echocardiographic images with anatomic specimens of equivalent valvular and supravalvular aortic obstruction. Specimens were part of the collection of the Department of Embryology. Fifty six patients were studied, and forty specimens with aortic obstruction were analyzed. Echocardiographic characteristics: Thirty one (55.3% patients were women and twenty five (44.7% men. Valvular aortic obstruction was found in Thirty six patients (64.3 % and supravalvular aortic obstruction in twenty (35.7%. Anatomic characteristics: Of the forty specimens examined, twenty one (52.5% had valvular aortic obstruction and nineteen (47.5% supravalvular aortic obstruction. The anatomoechocardiographic correlation clearly showed that the anatomic findings of the specimen hearts and aortas corresponded to echocardiographic images of valvular and supravalvular aortic obstruction and provided solid corroboration of echocardiographic diagnoses.

  5. Acute Aortic Arch Perforation During Transcatheter Aortic Valve Replacement in Bicuspid Aortic Stenosis and a Gothic Aortic Arch

    DEFF Research Database (Denmark)

    Millan-Iturbe, Oscar; Sawaya, Fadi J.; Bieliauskas, Gintautas

    2017-01-01

    AS because of its unique anatomic features. This case report describes an acute aortic perforation during delivery of a transcatheter heart valve to treat a severe bicuspid AS with a “gothic aortic arch”; more careful evaluation of the preprocedural multislice computed tomographic scan would have unveiled...

  6. Impaired Muscle Oxygenation and Elevated Exercise Blood Pressure in Hypertensive Patients: Links With Vascular Stiffness.

    Science.gov (United States)

    Dipla, Konstantina; Triantafyllou, Areti; Koletsos, Nikolaos; Papadopoulos, Stavros; Sachpekidis, Vasileios; Vrabas, Ioannis S; Gkaliagkousi, Eugenia; Zafeiridis, Andreas; Douma, Stella

    2017-08-01

    This study examined in vivo (1) skeletal muscle oxygenation and microvascular function, at rest and during handgrip exercise, and (2) their association with macrovascular function and exercise blood pressure (BP), in newly diagnosed, never-treated patients with hypertension and normotensive individuals. Ninety-one individuals (51 hypertensives and 40 normotensives) underwent office and 24-hour ambulatory BP, arterial stiffness, and central aortic BP assessment, followed by a 5-minute arterial occlusion and a 3-minute submaximal handgrip exercise. Changes in muscle oxygenated and deoxygenated hemoglobin and tissue oxygen saturation were continuously monitored by near-infrared spectroscopy and beat-by-beat BP by Finapres. Hypertensives had higher ( P age and body mass index (BMI) adjusted). When exercising at the same submaximal intensity, hypertensives required a significantly greater ( P hypertension exhibit prominent reductions in in vivo indices of skeletal muscle oxidative capacity, suggestive of mitochondrial dysfunction, and blunted muscle microvascular reactivity. These dysfunctions were associated with higher aortic systolic BP and arterial stiffness. Dysregulations in muscle oxygen delivery/utilization and microvascular stiffness, in hypertensive patients, partially contribute to their exaggerated BP during exercise. © 2017 American Heart Association, Inc.

  7. Dynamic stiffness of suction caissons

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Liingaard, Morten; Andersen, Lars

    This report concerns the dynamic soil-structure interaction of steel suction caissons applied as foundations for offshore wind turbines. An emphasis is put on torsional vibrations and coupled sliding/rocking motion, and the influence of the foundation geometry and the properties of the surrounding...... soil is examined. The soil is simplified as a homogenous linear viscoelastic material and the dynamic stiffness of the suction caisson is expressed in terms of dimensionless frequency-dependent coefficients corresponding to the different degrees of freedom. The dynamic stiffness coefficients...... for the skirted foundation are evaluated by means of a three-dimensional coupled boundary element/finite element model. Comparisons with known analytical and numerical solutions indicate that the static and dynamic behaviour of the foundation are predicted accurately with the applied model. The analysis has been...

  8. Minimally invasive aortic valve replacement

    DEFF Research Database (Denmark)

    Foghsgaard, Signe; Schmidt, Thomas Andersen; Kjaergard, Henrik K

    2009-01-01

    In this descriptive prospective study, we evaluate the outcomes of surgery in 98 patients who were scheduled to undergo minimally invasive aortic valve replacement. These patients were compared with a group of 50 patients who underwent scheduled aortic valve replacement through a full sternotomy...... operations were completed as mini-sternotomies, 4 died later of noncardiac causes. The aortic cross-clamp and perfusion times were significantly different across all groups (P replacement...... is an excellent operation in selected patients, but its true advantages over conventional aortic valve replacement (other than a smaller scar) await evaluation by means of randomized clinical trial. The "extended mini-aortic valve replacement" operation, on the other hand, is a risky procedure that should...

  9. Acute Type II Aortic Dissection with Severe Aortic Regurgitation and Chronic Descending Aortic Dissection in Pregnant Patient with Marfan Syndrome.

    Science.gov (United States)

    Lee, Seok-Soo; Jung, Tae-Eun; Lee, Dong Hyup

    2012-12-01

    Aortic dilatation and dissection are severe complications during pregnancy that can be fatal to both the mother and the fetus. The risks of these complications are especially high in pregnant patients with Marfan syndrome; however, incidents of descending aortic dissection are very rare. This case report involves a successful Bentall procedure for and recovery from a rare aortic dissection in a pregnant Marfan patient who developed acute type II aortic dissection with severe aortic regurgitation and chronic descending aortic dissection immediately after Cesarean section. Regular follow-up will be needed to monitor the descending aortic dissection.

  10. Abdominal Aortic Emergencies.

    Science.gov (United States)

    Lech, Christie; Swaminathan, Anand

    2017-11-01

    This article discusses abdominal aortic emergencies. There is a common thread of risk factors and causes of these diseases, including age, male gender, hypertension, dyslipidemia, and connective tissue disorders. The most common presenting symptom of these disorders is pain, usually in the chest, flank, abdomen, or back. Computed tomography scan is the gold standard for diagnosis of pathologic conditions of the aorta in the hemodynamically stable patient. Treatment consists of a combination of blood pressure and heart rate control and, in many cases, emergent surgical intervention. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Quantum Proximity Resonances

    International Nuclear Information System (INIS)

    Heller, E.J.

    1996-01-01

    It is well known that at long wavelengths λ an s-wave scatterer can have a scattering cross section σ on the order of λ 2 , much larger than its physical size, as measured by the range of its potential. Very interesting phenomena can arise when two or more identical scatterers are placed close together, well within one wavelength. We show that, for a pair of identical scatterers, an extremely narrow p-wave open-quote open-quote proximity close-quote close-quote resonance develops from a broader s-wave resonance of the individual scatterers. A new s-wave resonance of the pair also appears. The relation of these proximity resonances (so called because they appear when the scatterers are close together) to the Thomas and Efimov effects is discussed. copyright 1996 The American Physical Society

  12. Acute Type II Aortic Dissection with Severe Aortic Regurgitation and Chronic Descending Aortic Dissection in Pregnant Patient with Marfan Syndrome

    OpenAIRE

    Lee, Seok-Soo; Jung, Tae-Eun; Lee, Dong Hyup

    2012-01-01

    Aortic dilatation and dissection are severe complications during pregnancy that can be fatal to both the mother and the fetus. The risks of these complications are especially high in pregnant patients with Marfan syndrome; however, incidents of descending aortic dissection are very rare. This case report involves a successful Bentall procedure for and recovery from a rare aortic dissection in a pregnant Marfan patient who developed acute type II aortic dissection with severe aortic regurgitat...

  13. Valve-sparing aortic root replacement and aortic valve repair in a patient with acromegaly and aortic root dilatation

    Directory of Open Access Journals (Sweden)

    Karel Van Praet

    2015-07-01

    Full Text Available Aortic regurgitation and dilatation of the aortic root and ascending aorta are severe complications of acromegaly. The current trend for management of an aortic root aneurysm is valve-sparing root replacement as well as restoring the diameter of the aortic sinotubular junction (STJ and annulus. Our case report supports the recommendation that in patients with acromegaly, severe aortic root involvement may indicate the need for surgery.

  14. Sweet potato (Ipomoea batatas) attenuates diet-induced aortic stiffening independent of changes in body composition.

    Science.gov (United States)

    Garner, Tyler; Ouyang, An; Berrones, Adam J; Campbell, Marilyn S; Du, Bing; Fleenor, Bradley S

    2017-08-01

    We hypothesized a sweet potato intervention would prevent high-fat (HF) diet-induced aortic stiffness, which would be associated with decreased arterial oxidative stress and increased mitochondrial uncoupling. Young (8-week old) C57BL/6J mice were randomly divided into 4 groups: low fat (LF; 10% fat), HF (60% fat), low-fat sweet potato (LFSP; 10% fat containing 260.3 μg/kcal sweet potato), or high-fat sweet potato diet (HFSP; 60% fat containing 260.3 μg/kcal sweet potato) for 16 weeks. Compared with LF and LFSP, HF- and HFSP-fed mice had increased body mass and percent fat mass with lower percent lean mass (all, P Sweet potato intervention did not influence body composition (all, P > 0.05). Arterial stiffness, assessed by aortic pulse wave velocity and ex vivo mechanical testing of the elastin region elastic modulus (EEM) was greater in HF compared with LF and HFSP animals (all, P sweet potato attenuates diet-induced aortic stiffness independent of body mass and composition, which is associated with a normalization of arterial oxidative stress possibly due to mitochondrial uncoupling.

  15. Unusual Case of Overt Aortic Dissection Mimicking Aortic Intramural Hematoma

    Directory of Open Access Journals (Sweden)

    Kushtrim Disha

    2016-04-01

    Full Text Available We report an interesting case in which overt aortic dissection mimicked two episodes of aortic intramural hematoma (IMH (Stanford A, DeBakey I. This took place over the course of four days and had a major influence on the surgical treatment strategy. The first episode of IMH regressed completely within 15 hours after it was clinically diagnosed and verified using imaging techniques. The recurrence of IMH was detected three days thereafter, resulting in an urgent surgical intervention. Overt aortic dissection with evidence of an intimal tear was diagnosed intraoperatively.

  16. Measurement of the aortic diameter in the asymptomatic Korean population: Assessment with multidetector CT

    International Nuclear Information System (INIS)

    Lee, Sang Hwan; Lee, Whal; Choi, Hyuck Jae; Kim, Dae Jin; Park, Eun Ah; Chung, Jin Wook; Park, Jae Hyung

    2013-01-01

    To determine normal reference values for aortic diameters in asymptomatic Korean adults. Three hundred adults without signs or symptoms of cardiovascular diseases were enrolled in this study. Aortic diameters were measured at nine predetermined levels on CT images. Aortic diameter measurements were adjusted for body surface area. Analysis of data was performed with regard to age, sex, weight, height and hypertension. Aortic diameters were 2.99 ± 0.57 cm at the ascending aorta, 2.54 ± 0.35 cm at the transverse aortic arch, 2.36 ± 0.35 cm at the proximal descending thoracic aorta (DTA), 2.23 ± 0.37 cm at the mid DTA, 2.17 ± 0.38 cm at the distal DTA, 2.16 ± 0.37 cm at the thoracoabdominal junction, 2.10, 00B1, 0.35 cm at the level of the celiac axis, 1.94, 00B1, 0.36 cm at the suprarenal aorta, 1.58 ± 0.24 cm at the aortic bifurcation. Men had slightly larger diameters than women (p < 0.05). All diameters increased with age and hypertension, with statistical significance (p < 0.01). And all aortic diameters increased with height (p < 0.05) except at the level of the aortic arch (p = 0.056), and increased with weight (p < 0.05) except at the level of the suprarenal aorta (p = 0.067). Male sex, higher weight and height, age and hypertension are associated with larger aortic diameters in asymptomatic Korean adults.

  17. Aortic root replacement after previous surgical intervention on the aortic valve, aortic root, or ascending aorta.

    Science.gov (United States)

    Kirsch, E W Matthias; Radu, N Costin; Mekontso-Dessap, Armand; Hillion, Marie-Line; Loisance, Daniel

    2006-03-01

    Aortic root replacement after a previous operation on the aortic valve, aortic root, or ascending aorta remains a major challenge. Records of 56 consecutive patients (44 men; mean age, 56.4 +/- 13.6 years) undergoing reoperative aortic root replacement between June 1994 and June 2005 were reviewed retrospectively. Reoperation was performed 9.4 +/- 6.7 years after the last cardiac operation. Indications for reoperation were true aneurysm (n = 14 [25%]), false aneurysm (n = 10 [18%]), dissection or redissection (n = 9 [16%]), structural or nonstructural valve dysfunction (n = 10 [18%]), prosthetic valve-graft infection (n = 12 [21%]), and miscellaneous (n = 1 [2%]). Procedures performed were aortic root replacement (n = 47 [84%]), aortic root replacement plus mitral valve procedure (n = 5 [9%]), and aortic root replacement plus arch replacement (n = 4 [7%]). In 14 (25%) patients coronary artery bypass grafting had to be performed unexpectedly during the same procedure or immediately after the procedure to re-establish coronary perfusion. Hospital mortality reached 17.9% (n = 10). Multivariate logistic regression analysis revealed the need for unplanned perioperative coronary artery bypass grafting as the sole independent risk factor for hospital death (P = .005). Actuarial survival was 83.8% +/- 4.9% at 1 month, 73.0% +/- 6.3% at 1 year, and 65.7% +/- 9.0% at 5 years after the operation. One patient had recurrence of endocarditis 6.7 months after the operation and required repeated homograft aortic root replacement. Reoperative aortic root replacement remains associated with a high postoperative mortality. The need to perform unplanned coronary artery bypass grafting during reoperative aortic root replacement is a major risk factor for hospital death. The optimal technique for coronary reconstruction in this setting remains to be debated.

  18. Reinforced aortic root reconstruction for acute type A aortic dissection involving the aortic root

    Directory of Open Access Journals (Sweden)

    Han Qing-qi

    2013-06-01

    Full Text Available OBJECTIVE: There are debates regarding the optimal approach for AAAD involving the aortic root. We described a modified reinforced aortic root reconstruction approach for treating AAAD involving the aortic root. METHODS: A total of 161 patients with AAAD involving the aortic root were treated by our modified reinforced aortic root reconstruction approach from January 1998 to December 2008. Key features of our modified approach were placement of an autologous pericardial patch in the false lumen, lining of the sinotubular junction lumen with a polyester vascular ring, and wrapping of the vessel with Teflon strips. Outcome measures included post-operative mortality, survival, complications, and level of aortic regurgitation. RESULTS: A total of 161 patients were included in the study (mean age: 43.3 1 15.5 years. The mean duration of follow-up was 5.1 1 2.96 years (2-12 years. A total of 10 (6.2% and 11 (6.8% patients died during hospitalization and during follow-up, respectively. Thirty-one (19.3% patients experienced postoperative complications. The 1-, 3-, 5-, and 10-year survival rates were 99.3%, 98%, 93.8%, and 75.5%, respectively. There were no instances of recurrent aortic dissection, aortic aneurysm, or pseudoaneurysm during the entire study period. The severity of aortic regurgitation dramatically decreased immediately after surgery (from 28.6% to 0% grade 3-4 and thereafter slightly increased (from 0% to 7.2% at 5 years and 9.1% at 10 years. CONCLUSION: This modified reinforced aortic root reconstruction was feasible, safe and durable/effective, as indicated by its low mortality, low postoperative complications and high survival rate.

  19. Current indications for stentless aortic bioprostheses.

    Science.gov (United States)

    Hegazy, Yasser Y; Rayan, Amr; Bauer, Stefan; Keshk, Noha; Bauer, Kerstin; Ennker, Ina; Ennker, Jürgen

    2018-01-01

    The best aortic prostheses have been debated for decades. The introduction of stentless aortic bioprostheses was aimed at improving hemodynamics and potentially the durability of aortic bioprostheses. Despite the good short- and long-term outcomes after implantation of stentless aortic bioprostheses, their use remains limited owing to the technically demanding implantation techniques. Nevertheless, stentless aortic bioprostheses might be of special benefit in certain indications, where they could be a valuable addition to the surgical armamentarium.

  20. Coupling between the Output Force and Stiffness in Different Variable Stiffness Actuators

    Directory of Open Access Journals (Sweden)

    Amir Jafari

    2014-08-01

    Full Text Available The fundamental objective in developing variable stiffness actuators is to enable the actuator to deliberately tune its stiffness. This is done through controlling the energy flow extracted from internal power units, i.e., the motors of a variable stiffness actuator (VSA. However, the stiffness may also be unintentionally affected by the external environment, over which, there is no control. This paper analysis the correlation between the external loads, applied to different variable stiffness actuators, and their resultant output stiffness. Different types of variable stiffness actuators have been studied considering springs with different types of nonlinearity. The results provide some insights into how to design the actuator mechanism and nonlinearity of the springs in order to increase the decoupling between the load and stiffness in these actuators. This would significantly widen the application range of a variable stiffness actuator.

  1. The mechanical benefit of medial support screws in locking plating of proximal humerus fractures.

    Directory of Open Access Journals (Sweden)

    Wen Zhang

    Full Text Available BACKGROUND: The purpose of this study was to evaluate the biomechanical advantages of medial support screws (MSSs in the locking proximal humeral plate for treating proximal humerus fractures. METHODS: Thirty synthetic left humeri were randomly divided into 3 subgroups to establish two-part surgical neck fracture models of proximal humerus. All fractures were fixed with a locking proximal humerus plate. Group A was fixed with medial cortical support and no MSSs; Group B was fixed with 3 MSSs but without medial cortical support; Group C was fixed with neither medial cortical support nor MSSs. Axial compression, torsional stiffness, shear stiffness, and failure tests were performed. RESULTS: Constructs with medial support from cortical bone showed statistically higher axial and shear stiffness than other subgroups examined (P<0.0001. When the proximal humerus was not supported by medial cortical bone, locking plating with medial support screws exhibited higher axial and torsional stiffness than locking plating without medial support screws (P ≤ 0.0207. Specimens with medial cortical bone failed primarily by fracture of the humeral shaft or humeral head. Specimens without medial cortical bone support failed primarily by significant plate bending at the fracture site followed by humeral head collapse or humeral head fracture. CONCLUSIONS: Anatomic reduction with medial cortical support was the stiffest construct after a simulated two-part fracture. Significant biomechanical benefits of MSSs in locking plating of proximal humerus fractures were identified. The reconstruction of the medial column support for proximal humerus fractures helps to enhance mechanical stability of the humeral head and prevent implant failure.

  2. Morphological risk factors of stroke during thoracic endovascular aortic repair.

    Science.gov (United States)

    Kotelis, Drosos; Bischoff, Moritz S; Jobst, Bertram; von Tengg-Kobligk, Hendrik; Hinz, Ulf; Geisbüsch, Philipp; Böckler, Dittmar

    2012-12-01

    This study aims to identify independent factors correlating to an increased risk of perioperative stroke during thoracic endovascular aortic repair (TEVAR). A prospective maintained TEVAR database, medical records, and imaging studies of 300 patients (205 men; median age of all, 66 years, range 21-89), who underwent TEVAR between March 1997 and February 2011, were reviewed. Preoperative CT data sets were reviewed by two experienced radiologists with focus on the atheroma burden in the aortic arch (grade I, normal, to grade V, ulcerated or pedunculated atheroma). Aortic arch geometry (arch types I-III) was documented. Further parameters included in the univariate analysis were age, gender, urgency of repair, duration of procedure, adenosine-induced cardiac arrest or rapid pacing, proximal landing zone, left subclavian artery (LSA) coverage, and number of stent grafts. Multivariate logistic regression analysis was performed to assess the independent correlations of potential risk factors. Atherosclerotic aneurysm was the most common pathology (44%). One hundred and fifty-four of our patients (51%) were treated under urgent or emergent conditions. Seventeen percent of all patients had significant arch atheroma (grade IV or V), and 43% had a steep type III aortic arch. The perioperative stroke was 4% (12 patients; median age, 73 years, range 31-78). Two strokes were lethal (0.7%). All strokes were classified as embolic based on imaging characteristics. In eight patients, strokes were located in the left cerebral hemisphere (seven of them in the anterior and one in the posterior circulation). Four stroke patients (one in the left posterior circulation) underwent LSA coverage without revascularization. Three stroke patients had severe arch atheroma grade V. Five patients suffering stroke were recognized to have a type III aortic arch. Strokes were equally distributed between zones 0-2 vs. 3-4 (n = 6 each, 5 vs. 3.3%). The highest incidence was found in zone 1 (11

  3. Tobacco smoking and aortic aneurysm

    DEFF Research Database (Denmark)

    Sode, Birgitte F; Nordestgaard, Børge; Grønbæk, Morten

    2013-01-01

    BACKGROUND: We determined the predictive power of tobacco smoking on aortic aneurysm as opposed to other risk factors in the general population. METHODS: We recorded tobacco smoking and other risk factors at baseline, and assessed hospitalization and death from aortic aneurysm in 15,072 individuals...... aneurysm in males and females consuming above 20g tobacco daily was 3.5% and 1.3%, among those >60years with plasma cholesterol >5mmol/L and a systolic blood pressure >140mmHg. CONCLUSIONS: Tobacco smoking is the most important predictor of future aortic aneurysm outcomes in the general population...

  4. [Aortic root dilatation rate in pediatric patients with Marfan syndrome treated with losartan].

    Science.gov (United States)

    Mariucci, Elisabetta; Guidarini, Marta; Donti, Andrea; Lovato, Luigi; Wischmeijer, Anita; Angeli, Emanuela; Gargiulo, Gaetano D; Picchio, Fernando M; Bonvicini, Marco

    2015-12-01

    Medical therapy with angiotensin II receptor blockers/angiotensin-converting enzyme inhibitors and/or beta-blockers was reported to reduce aortic root dilatation rates in pediatric patients with Marfan syndrome. No data are available in the literature on losartan effects after 3 years of therapy. The aim of our study was to establish whether losartan reduces aortic root dilatation rates in pediatric patients with Marfan syndrome in the mid and long term. This is a retrospective analysis of 38 pediatric patients with Marfan syndrome followed at the Marfan Clinic of S. Orsola-Malpighi Hospital of the University of Bologna (Italy). Aortic diameters were measured at sinuses of Valsalva and proximal ascending aorta with transthoracic echocardiography. After a mean follow-up of 4.5 ± 2.5 years (range 2-9 years), aortic root z score at sinuses of Valsalva and proximal ascending aorta remained stable. The average annual rate of change in aortic root z score was -0.1 ± 0.4 and 0 ± 0.3 at sinuses of Valsalva and proximal ascending aorta, respectively. The mean dose of losartan was 0.7 ± 0.3 mg/kg/day. Three patients were non-responders, probably because of late beginning or low dose of therapy. Eight patients underwent cardiac surgery (aortic root surgery in 5 and mitral valve repair in 3), all of them started losartan later in life. Despite the retrospective design of the study and the small sample size, a beneficial effect of losartan therapy was observed in pediatric patients with Marfan syndrome in the mid and long term. Late beginning or low doses of losartan can turn off the effects of therapy.

  5. Proximity friction reexamined

    International Nuclear Information System (INIS)

    Krappe, H.J.

    1989-01-01

    The contribution of inelastic excitations to radial and tangential friction form-factors in heavy-ion collisions is investigated in the frame-work of perturbation theory. The dependence of the form factors on the essential geometrical and level-density parameters of the scattering system is exhibited in a rather closed form. The conditions for the existence of time-local friction coefficients are discussed. Results are compared to form factors from other models, in particular the transfer-related proximity friction. For the radial friction coefficient the inelastic excitation mechanism seems to be the dominant contribution in peripheral collisions. (orig.)

  6. Proximal femoral fractures.

    Science.gov (United States)

    Webb, Lawrence X

    2002-01-01

    Fractures of the proximal femur include fractures of the head, neck, intertrochanteric, and subtrochanteric regions. Head fractures commonly accompany dislocations. Neck fractures and intertrochanteric fractures occur with greatest frequency in elderly patients with a low bone mineral density and are produced by low-energy mechanisms. Subtrochanteric fractures occur in a predominantly strong cortical osseous region which is exposed to large compressive stresses. Implants used to address these fractures must be able to accommodate significant loads while the fractures consolidate. Complications secondary to these injuries produce significant morbidity and include infection, nonunion, malunion, decubitus ulcers, fat emboli, deep venous thrombosis, pulmonary embolus, pneumonia, myocardial infarction, stroke, and death.

  7. Acute Aortic Dissection Mimicking STEMI in the Catheterization Laboratory: Early Recognition Is Mandatory

    Directory of Open Access Journals (Sweden)

    Alessio Arrivi

    2012-01-01

    Full Text Available Coronary malperfusion due to type A aortic dissection is a life-threatening condition where timely recognition and treatment are mandatory. A 77-year-old woman underwent an acute evolving type A aortic dissection mimicking acute myocardial infarction. Two pathophysiologic mechanisms are discussed: either thrombosis migrating from a previously treated giant aneurism of proximal left anterior descending or a local arterial complication due to left main stenting. Recognition of these occurrences in the catheterization laboratory is important to look immediately for surgery.

  8. The bicuspid aortic valve and its relation to aortic dilation

    Directory of Open Access Journals (Sweden)

    Shi-Min Yuan

    2010-01-01

    Full Text Available BACKGROUND: A bicuspid aortic valve (BAV is a common congenital heart disease, which affects 1-2% of the population. However, the relationship between BAVs and aortic dilation has not been sufficiently elucidated. METHODS: A total of 241 BAV patients who were referred to this hospital for cardiac surgey over a 4.75-year period were included in this study. In addition to the clinical characteristics of the included patients, the morphological features of the aortic valve and aorta, the length of the left main coronary artery, and the laboratory findings (the coagulation and hematological parameters as well as the total cholesterol concentration were determined and compared with those of the tricuspid aortic valve (TAV patients. RESULTS: The BAV patients were younger than the TAV patients for a valve surgery in the last 3 months of the study period. The BAV patients were predominantly male. Most of the BAVs that were surgically treated were stenotic, regurgitant, or combined, and only 19 (7.88% were normally functioning valves. According to echocardiography or operative records, 148 (78.31% were type A, 31 (16.40% were type B, and 10 (5.29% were type C. The left main coronary artery was much shorter in the BAV patients than it was in the TAV patients. There was no significant difference between BAV and TAV patients in the total cholesterol concentrations; whereas differences were noted between patients receiving lipid-lowering therapy and those not receiving lipid-lowering therapy. The dimensions of the aortic root, sinotubular junction, and ascending aorta were beyond normal limits, while they were significantly smaller in the BAV patients than in the TAV patients. They were also much smaller in patients receiving statin therapy than those not receiving statin therapy in both groups. Moreover, the aortic dilation in the BAV group was found to be significantly associated with patient age. CONCLUSIONS: The BAV patients developed aortic wall and

  9. Echosonography with proximity sensors

    International Nuclear Information System (INIS)

    Thaisiam, W; Laithong, T; Meekhun, S; Chaiwathyothin, N; Thanlarp, P; Danworaphong, S

    2013-01-01

    We propose the use of a commercial ultrasonic proximity sensor kit for profiling an altitude-varying surface by employing echosonography. The proximity sensor kit, two identical transducers together with its dedicated operating circuit, is used as a profiler for the construction of an image. Ultrasonic pulses are emitted from one of the transducers and received by the other. The time duration between the pulses allows us to determine the traveling distance of each pulse. In the experiment, the circuit is used with the addition of two copper wires for directing the outgoing and incoming signals to an oscilloscope. The time of flight of ultrasonic pulses can thus be determined. Square grids of 5 × 5 cm 2 are made from fishing lines, forming pixels in the image. The grids are designed to hold the detection unit in place, about 30 cm above a flat surface. The surface to be imaged is constructed to be height varying and placed on the flat surface underneath the grids. Our result shows that an image of the profiled surface can be created by varying the location of the detection unit along the grid. We also investigate the deviation in relation to the time of flight of the ultrasonic pulse. Such an experiment should be valuable for conveying the concept of ultrasonic imaging to physical and medical science undergraduate students. Due to its simplicity, the setup could be made in any undergraduate laboratory relatively inexpensively and it requires no complex parts. The results illustrate the concept of echosonography. (paper)

  10. Abdominal aortic aneurysms

    DEFF Research Database (Denmark)

    Lindholt, Jes S.

    2010-01-01

    Although the number of elective operations for abdominal aortic aneurysms (AAA) is increasing, the sex- and age-standardised mortality rate of AAAs continues to rise, especially among men aged 65 years or more. The lethality of ruptured AAA continues to be 80-95%, compared with 5-7% by elective...... surgery of symptomfree AAA. In order to fulfil all WHO, European, and Danish criteria for screening, a randomised hospitalbased screening trial of 12,639 65-73 year old men in Viborg County (Denmark) was initiated in 1994. It seemed that US screening is a valid, suitable and acceptable method of screening...... patients without previous hospital discharge diagnoses due to cardiovascular disease than among similar men without AAA. The absolute risk difference after 5 years was 16%. So, they will benefit from general cardiovascular preventive action as smoking cessation, statins and low-dose aspirin, which could...

  11. Abdominal aortic aneurysm surgery

    DEFF Research Database (Denmark)

    Gefke, K; Schroeder, T V; Thisted, B

    1994-01-01

    The goal of this study was to identify patients who need longer care in the ICU (more than 48 hours) following abdominal aortic aneurysm (AAA) surgery and to evaluate the influence of perioperative complications on short- and long-term survival and quality of life. AAA surgery was performed in 553...... patients, 51 (9%) of whom died within the first 48 hours. Of the 502 patients who survived for more than 48 hours, 109 required ICU therapy for more than 48 hours, whereas 393 patients were in the ICU for less than 48 hours. The incidence of preoperative risk factors was similar for the two groups...... combined failed to permit identification of patients in whom the perioperative survival rate was 0%. Even 20% of patients with multiorgan failure survived for 6 months. Of those patients who needed ICU therapy for more than 48 hours, 41 (38%) were alive at the end of 1988. In response to a questionnaire...

  12. Variations of the aortic arch - a study on the most common branching patterns

    Energy Technology Data Exchange (ETDEWEB)

    Muller, Marguerite; Schmitz, Bernd L; Schick, Melanie; Schloetzer, Wiebke (Dept. of Diagnostic and Interventional Radiology, Section Neuroradiology, Univ. Ulm (Germany)), email: marguerite.mueller@uni-ulm.de; Pauls, Sandra (Dept. of Diagnostic and Interventional Radiology, Univ. Ulm (Germany)); Roehrer, Stefan; Kapapa, Thomas (Dept. of Neurosurgery, Univ. Ulm (Germany))

    2011-09-15

    Background: Anatomical variants of the aortic arch and its branching patterns often appear as an incidental finding during routine computed tomography (CT) scanning. These variations can be of relevance when performing angiography or endovascular interventions and may cause symptoms such as dysphagia. Purpose: To analyze common anatomical variations found within the arteries originating from the aortic arch in patients using contrast CT imaging techniques. Material and Methods: A total of 2033 contrast CT scans were analyzed. To obtain a truly representative sample, cases were chosen from different hospital departments without previous knowledge of the patient history. Results: The total percentage of variations within the analyzed patients was 13.3%. In 8.0% a truncus bicaroticus was found. 4.2% of the patients showed a left vertebral artery originating directly from the aortic arch, mostly proximal, and in 1 case distal to the left subclavian artery. In 1.0% we found an aberrant right subclavian artery. We also found a single case of a right descending aortic arch. Conclusion: Variations of the aortic arch and its branching are frequently found, mostly as an incidental finding during routine diagnostic scanning. A contrast-enhanced CT scan is a good method with which to study the aortic arch and its associated branching pattern

  13. Overview of current surgical strategies for aortic disease in patients with Marfan syndrome.

    Science.gov (United States)

    Miyahara, Shunsuke; Okita, Yutaka

    2016-09-01

    Marfan syndrome is a heritable, systemic disorder of the connective tissue with a high penetrance, named after Dr. Antoine Marfan. The most clinically important manifestations of this syndrome are cardiovascular pathologies which cause life-threatening events, such as acute aortic dissections, aortic rupture and regurgitation of the aortic valve or other artrioventricular valves leading to heart failure. These events play important roles in the life expectancy of patients with this disorder, especially prior to the development of effective surgical approaches for proximal ascending aortic disease. To prevent such catastrophic aortic events, a lower threshold has been recommended for prophylactic interventions on the aortic root. After prophylactic root replacement, disease in the aorta beyond the root and distal to the arch remains a cause for concern. Multiple surgeries are required throughout a patient's lifetime that can be problematic due to distal lesions complicated by dissection. Many controversies in surgical strategies remain, such as endovascular repair, to manage such complex cases. This review examines the trends in surgical strategies for the treatment of cardiovascular disease in patients with Marfan syndrome, and current perspectives in this field.

  14. Variations of the aortic arch - a study on the most common branching patterns

    International Nuclear Information System (INIS)

    Muller, Marguerite; Schmitz, Bernd L; Schick, Melanie; Schloetzer, Wiebke; Pauls, Sandra; Roehrer, Stefan; Kapapa, Thomas

    2011-01-01

    Background: Anatomical variants of the aortic arch and its branching patterns often appear as an incidental finding during routine computed tomography (CT) scanning. These variations can be of relevance when performing angiography or endovascular interventions and may cause symptoms such as dysphagia. Purpose: To analyze common anatomical variations found within the arteries originating from the aortic arch in patients using contrast CT imaging techniques. Material and Methods: A total of 2033 contrast CT scans were analyzed. To obtain a truly representative sample, cases were chosen from different hospital departments without previous knowledge of the patient history. Results: The total percentage of variations within the analyzed patients was 13.3%. In 8.0% a truncus bicaroticus was found. 4.2% of the patients showed a left vertebral artery originating directly from the aortic arch, mostly proximal, and in 1 case distal to the left subclavian artery. In 1.0% we found an aberrant right subclavian artery. We also found a single case of a right descending aortic arch. Conclusion: Variations of the aortic arch and its branching are frequently found, mostly as an incidental finding during routine diagnostic scanning. A contrast-enhanced CT scan is a good method with which to study the aortic arch and its associated branching pattern

  15. Evaluation of the aortic anulus

    International Nuclear Information System (INIS)

    Link, K.M.; Margosian, P.

    1991-01-01

    This paper evaluates the efficacy of echocardiography and MR imaging for measuring the aortic anulus in patients who are candidates for aortic valve replacement. The MR imaging study was performed on a 1.5-T system, and the results were compared with echocardiography results obtained with use of a Toshiba system with a 2.5-mHz transducer. The aortic valve anulus was evaluated in the coronal, long-axis, and short-axis views with the MR imaging technique and in the right parasternal suprasternal, and apical projections with the echocardiographic technique. Twenty-four patients studied with MR imaging and echocardiography went on to have aortic valve replacement. When compared with surgical results, MR imaging had an r value of .95 while echocardiography had an r value of .70

  16. Abnormal pulmonary artery stiffness in pulmonary arterial hypertension: in vivo study with intravascular ultrasound.

    Directory of Open Access Journals (Sweden)

    Edmund M T Lau

    Full Text Available BACKGROUND: There is increasing recognition that pulmonary artery stiffness is an important determinant of right ventricular (RV afterload in pulmonary arterial hypertension (PAH. We used intravascular ultrasound (IVUS to evaluate the mechanical properties of the elastic pulmonary arteries (PA in subjects with PAH, and assessed the effects of PAH-specific therapy on indices of arterial stiffness. METHOD: Using IVUS and simultaneous right heart catheterisation, 20 pulmonary segments in 8 PAH subjects and 12 pulmonary segments in 8 controls were studied to determine their compliance, distensibility, elastic modulus and stiffness index β. PAH subjects underwent repeat IVUS examinations after 6-months of bosentan therapy. RESULTS: AT BASELINE, PAH SUBJECTS DEMONSTRATED GREATER STIFFNESS IN ALL MEASURED INDICES COMPARED TO CONTROLS: compliance (1.50±0.11×10(-2 mm(2/mmHg vs 4.49±0.43×10(-2 mm(2/mmHg, p<0.0001, distensibility (0.32±0.03%/mmHg vs 1.18±0.13%/mmHg, p<0.0001, elastic modulus (720±64 mmHg vs 198±19 mmHg, p<0.0001, and stiffness index β (15.0±1.4 vs 11.0±0.7, p = 0.046. Strong inverse exponential associations existed between mean pulmonary artery pressure and compliance (r(2 = 0.82, p<0.0001, and also between mean PAP and distensibility (r(2 = 0.79, p = 0.002. Bosentan therapy, for 6-months, was not associated with any significant changes in all indices of PA stiffness. CONCLUSION: Increased stiffness occurs in the proximal elastic PA in patients with PAH and contributes to the pathogenesis RV failure. Bosentan therapy may not be effective at improving PA stiffness.

  17. Imaging techniques in transcatheter aortic valve replacement

    Directory of Open Access Journals (Sweden)

    Quaife RA

    2013-11-01

    Full Text Available Robert A Quaife, Jennifer Dorosz, John C Messenger, Ernesto E Salcedo Division of Cardiology, University of Colorado, Aurora, CO, USA Abstract: Calcific aortic stenosis is now understood as a complex valvular degenerative process sharing many risk factors with atherosclerosis. Once patients develop symptomatic calcific aortic stenosis, the only effective treatment is aortic valve replacement. In the past decade, transcatheter aortic valve replacement (TAVR has been developed as an alternative to surgery to treat severe calcific aortic stenosis. Cardiac imaging plays a pivotal role in the contemporary management of patients with calcific aortic stenosis, and particularly in patients being considered for TAVR, who demand detailed imaging of the aortic valve apparatus. In this review, we highlight the role of cardiac imaging for patient selection, procedural guidance, and evaluation of results of TAVR. Keywords: aortic stenosis, cardiovascular imaging, transcutaneous aortic valve replacement

  18. Alkaptonuria-associated aortic stenosis.

    Science.gov (United States)

    Lok, Zoe S Y; Goldstein, Jacob; Smith, Julian A

    2013-07-01

    Alkaptonuria is an autosomal recessive disorder of tyrosine metabolism, which results in accumulation of unmetabolized homogentisic acid and its oxidized product in various tissues, including the heart. Cardiovascular involvement is a rare but serious complication of the disease. We present two patients who have undergone successful aortic valve replacement for alkaptonuria-associated aortic stenosis along with a review of the literature. © 2013 Wiley Periodicals, Inc.

  19. Lower limb joint kinetics and ankle joint stiffness in the sprint start push-off.

    Science.gov (United States)

    Charalambous, Laura; Irwin, Gareth; Bezodis, Ian N; Kerwin, David

    2012-01-01

    Sprint push-off technique is fundamental to sprint performance and joint stiffness has been identified as a performance-related variable during dynamic movements. However, joint stiffness for the push-off and its relationship with performance (times and velocities) has not been reported. The aim of this study was to quantify and explain lower limb net joint moments and mechanical powers, and ankle stiffness during the first stance phase of the push-off. One elite sprinter performed 10 maximal sprint starts. An automatic motion analysis system (CODA, 200 Hz) with synchronized force plates (Kistler, 1000 Hz) collected kinematic profiles at the hip, knee, and ankle and ground reaction forces, providing input for inverse dynamics analyses. The lower-limb joints predominately extended and revealed a proximal-to-distal sequential pattern of maximal extensor angular velocity and positive power production. Pearson correlations revealed relationships (P push-off in different ways, depending on the phase of stance considered.

  20. The Effect of an Angiotensin Receptor Blocker on Arterial Stiffness in Type 2 Diabetes Mellitus Patients with Hypertension

    Directory of Open Access Journals (Sweden)

    Ji Hyun Kim

    2011-06-01

    Full Text Available BackgroundHypertension and type 2 diabetes mellitus are major risk factors for cardiovascular disease. This study analyzed the changes in central aortic waveforms and pulse wave velocity as well as related parameters after treatment with valsartan, an angiotensin II type 1 receptor blocker, in patients with type 2 diabetes and hypertension.MethodsWe used pulse wave analysis to measure central aortic waveform in a total of 98 subjects. In 47 of these patients, pulse wave velocity measurements were obtained before and after 12 weeks of treatment with valsartan.ResultsIn the central aortic waveform analysis, the aortic pulse pressure and augmentation index were significantly decreased after valsartan treatment, as was the aortic pulse wave velocity. Factors contributing to the improvement in pulse wave velocity were the fasting blood glucose and haemoglobin A1c levels.ConclusionShort-term treatment with valsartan improves arterial stiffness in patients with type 2 diabetes and hypertension, and the glucose status at baseline was associated with this effect.

  1. 3D Bioprinting of Heterogeneous Aortic Valve Conduits with Alginate/Gelatin Hydrogels

    Science.gov (United States)

    Duan, Bin; Hockaday, Laura A.; Kang, Kevin H.; Butcher, Jonathan T.

    2013-01-01

    Heart valve disease is a serious and growing public health problem for which prosthetic replacement is most commonly indicated. Current prosthetic devices are inadequate for younger adults and growing children. Tissue engineered living aortic valve conduits have potential for remodeling, regeneration, and growth, but fabricating natural anatomical complexity with cellular heterogeneity remain challenging. In the current study, we implement 3D bioprinting to fabricate living alginate/gelatin hydrogel valve conduits with anatomical architecture and direct incorporation of dual cell types in a regionally constrained manner. Encapsulated aortic root sinus smooth muscle cells (SMC) and aortic valve leaflet interstitial cells (VIC) were viable within alginate/gelatin hydrogel discs over 7 days in culture. Acellular 3D printed hydrogels exhibited reduced modulus, ultimate strength, and peak strain reducing slightly over 7-day culture, while the tensile biomechanics of cell-laden hydrogels were maintained. Aortic valve conduits were successfully bioprinted with direct encapsulation of SMC in the valve root and VIC in the leaflets. Both cell types were viable (81.4±3.4% for SMC and 83.2±4.0% for VIC) within 3D printed tissues. Encapsulated SMC expressed elevated alpha-smooth muscle actin when printed in stiff matrix, while VIC expressed elevated vimentin in soft matrix. These results demonstrate that anatomically complex, heterogeneously encapsulated aortic valve hydrogel conduits can be fabricated with 3D bioprinting. PMID:23015540

  2. Concepts to optimize stent-grafting of abdominal aortic aneurysms based on results of experimental studies; Konzepte zur Optimierung der Stentgraftversorgung von Bauchaortenaneurysmen auf der Basis tierexperimenteller Ergebnisse

    Energy Technology Data Exchange (ETDEWEB)

    Chavan, A.; Kirchhoff, T.; Baus, S.; Galanski, M. [Medizinische Hochschule Hannover (Germany). Abt. Diagnostische Radiologie 1; Pichlmaier, M. [Medizinische Hochschule Hannover (Germany). Leibniz Forschungslab. fuer Biotechnologie und Kuenstliche Organe an der Klinik fuer Thorax-, Herz- und Gefaesschirurgie

    2001-08-01

    Purpose. In the endoluminal therapy of abdominal aortic aneurysms, a short proximal aneurysm neck, endoleaks and the large size and stiffness of the introducer systems are responsible for many of the complications and sub-optimal outcomes. The purpose of the present review article is to to suggest strategies to minimize these complications based on the results of experimental studies in animals. Material and methods. After implanting various types of stents across the renal artery origins, the functional and morphological changes in the kidneys and renal vessels were studied by various authors. In order to prevent progressive widening of the proximal aneurysmal neck and graft dislocation, Sonesson et al. performed a laparoscopic banding around the proximal neck in pigs. To study the effects of endoleaks, Marty, Schurink and Pitton carried out pressure measurements in experimental aneurysms with and without endoleaks. Sakaguchi and Pavcnik developed the 'Twin-tube endografts' (TTEG) and the 'Bifurcated drum occluder endografts' (BDOEG) and tested them in dogs. Results. Up to 3 months after suprarenal stent placement, Chavan et al. detected no significant fall in the mean inulin clearance in sheep (140{+-}46 ml/min before, 137{+-}58 ml/min after). Nasim et al. and Malina et al. reported similar observations with respect to renal function. Suprarenal fixation may result in isolated thrombotic occlusions of the renal arteries and microinfarcts in the kidneys. Mean aortic diameters at the level of banding were significantly smaller in the animals with aortic banding as opposed to those in the control group without banding (8 mm vs 11 mm, p=0.004). The banding caused a secure proximal fixation of the stent-graft. Persistent endoleaks resulted in significantly higher intraaneurysmal pressures. Although the TTEG and the BDOEG stent-grafts required smaller sheaths, occlusions were observed in 8% (TTEG) and 60% (BDOEG) of the graft limbs. (orig.) [German

  3. Modified conduit preparation creates a pseudosinus in an aortic valve-sparing procedure for aneurysm of the ascending aorta.

    Science.gov (United States)

    Cochran, R P; Kunzelman, K S; Eddy, A C; Hofer, B O; Verrier, E D

    1995-06-01

    no evidence of congestive symptoms. One patient who had extensive thoracoabdominal aneurysmal disease has undergone subsequent replacement of the descending aorta to the level of the renal arteries and has done well. Aortic valve-sparing replacement of the aortic root is an excellent procedure for any patient with an ascending aortic aneurysm and an anatomically salvageable valve. We believe that by modifying the proximal conduit and creating a "pseudosinus" into which the leaflets can retract without contact of the cylindrical conduit we may increase the longevity of the native aortic valve in this procedure.

  4. Results of aortic root reimplantation in patients with ascending aortic aneurysm and concomitant aortic insufficiency

    Directory of Open Access Journals (Sweden)

    А. М. Чернявский

    2016-01-01

    Full Text Available Objective. The research was designed to evaluate the results of valve-sparing operations: aortic root reimplantation versus aortic valve reimplantation when repairing an ascending aortic aneurysm with concomitant aortic insufficiency.Methods. Within a blind prospective randomized study conducted over a period from 2011 to 2015, 64 patients underwent aortic valve-sparing surgery. The inclusion criteria were the presence of an aortic aneurysm of the ascending aorta exceeding 4.5 cm and concomitant aortic insufficiency. All patients were divided into two groups: FS-group, aortic root reimplantation (modified Florida Sleeve technique (n = 32 and D-group, aortic valve reimplantation (David procedure (n = 32. The average age of patients was 57±13 (23–73 years in the FS-group and 55±11 (15–72 years in the D-group (p = 0.54. Both groups had 78% of males (p>0.99. A Marfan syndrome was identified in 6% and 9% in the FS-group and D-group respectively (p>0.99. Mean diameter of the sinuses of Valsalva was 51±7 mm and 56±10 mm (p = 0.09, aortic insufficiency 2.6±0.7 and 2.8±0.8 (p = 0.15 in the FS-group and D-group respectively. In the FS-group and D-group LVEDD amounted to 5.5±0.7 mm and 5.9±1.0 mm (p = 0.09 respectively. All patients took echocardiography in the preoperative, postoperative and follow-up periods.Results. In the long-term period, the degree of aortic regurgitation was 1.2±0.1 in the FS-group and 1.3±0.6 in the D-group (p = 0.72. LVEDD was 123±23 mm in the FS-group and 139.6±80 mm in the D-group at follow-up (p = 0.77. There were no statistically significant differences in the analysis of complications. Overall 30-day in-hospital mortality was 7.8%. There were 2 (6.3% deaths in the FS-group and 3 (9.4% in the D-group (p = 0.5.Late mortality was 6.3% in the FS-group and 3.1% in the D-group (p>0.99. Cumulative survival at 4 years was 84.3% and 84.8% in the FS-group and the D-group respectively (p = 0.94. Cumulative freedom from

  5. Children's proximal societal conditions

    DEFF Research Database (Denmark)

    Stanek, Anja Hvidtfeldt

    2018-01-01

    that is above or outside the institutional setting or the children’s everyday life, but something that is represented through societal structures and actual persons participating (in political ways) within the institutional settings, in ways that has meaning to children’s possibilities to participate, learn...... and develop. Understanding school or kindergarten as (part of) the children’s proximal societal conditions for development and learning, means for instance that considerations about an inclusive agenda are no longer simply thoughts about the school – for economic reasons – having space for as many pupils...... as possible (schools for all). Such thoughts can be supplemented by reflections about which version of ‘the societal’ we wish to present our children with, and which version of ‘the societal’ we wish to set up as the condition for children’s participation and development. The point is to clarify or sharpen...

  6. Proximity detection system underground

    Energy Technology Data Exchange (ETDEWEB)

    Denis Kent [Mine Site Technologies (Australia)

    2008-04-15

    Mine Site Technologies (MST) with the support ACARP and Xstrata Coal NSW, as well as assistance from Centennial Coal, has developed a Proximity Detection System to proof of concept stage as per plan. The basic aim of the project was to develop a system to reduce the risk of the people coming into contact with vehicles in an uncontrolled manner (i.e. being 'run over'). The potential to extend the developed technology into other areas, such as controls for vehicle-vehicle collisions and restricting access of vehicle or people into certain zones (e.g. non FLP vehicles into Hazardous Zones/ERZ) was also assessed. The project leveraged off MST's existing Intellectual Property and experience gained with our ImPact TRACKER tagging technology, allowing the development to be fast tracked. The basic concept developed uses active RFID Tags worn by miners underground to be detected by vehicle mounted Readers. These Readers in turn provide outputs that can be used to alert a driver (e.g. by light and/or audible alarm) that a person (Tag) approaching within their vicinity. The prototype/test kit developed proved the concept and technology, the four main components being: Active RFID Tags to send out signals for detection by vehicle mounted receivers; Receiver electronics to detect RFID Tags approaching within the vicinity of the unit to create a long range detection system (60 m to 120 m); A transmitting/exciter device to enable inner detection zone (within 5 m to 20 m); and A software/hardware device to process & log incoming Tags reads and create certain outputs. Tests undertaken in the laboratory and at a number of mine sites, confirmed the technology path taken could form the basis of a reliable Proximity Detection/Alert System.

  7. Sixteen-Year Experience of David and Bentall Procedures in Acute Type A Aortic Dissection.

    Science.gov (United States)

    Yang, Bo; Patel, Himanshu J; Sorek, Claire; Hornsby, Whitney E; Wu, Xiaoting; Ward, Sarah; Thomas, Marc; Driscoll, Anisa; Waidley, Victoria A; Norton, Elizabeth L; Likosky, Donald S; Deeb, G Michael

    2018-03-01

    To examine short-term and midterm outcomes after the David and Bentall procedures in patients with an acute type A aortic dissection. Between 2001 and 2017, patients (n = 135) with acute type A aortic dissection underwent an aortic root replacement with either the David (n = 40) or Bentall (n = 95) procedure. Perioperative outcome, reoperation rate, aortic valve function, and long-term survival were evaluated. The median age of the entire cohort was 56 years. Rates of malperfusion (21%), shock (16%), history of renal failure (4%), and extent of surgery were similar between David and Bentall groups. However, the David group was significantly younger (45 versus 61 years) with less hypertension (45% versus 66%), coronary artery disease (0% versus 17%), valvulopathy (5% versus 19%), and prior cardiac surgery (5% versus 21%). Overall operative mortality was 9.6% (David 3% and Bentall 13%). Composite outcome comprising myocardial infarction, stroke, new-onset renal failure, and operative mortality was 18% in the entire cohort (David 5% and Bentall 23%). In the David group, the freedom of moderate aortic insufficiency was 95% at 10 years. The rate of reoperation for pathology of the proximal aorta or aortic valve was 0% and 2% for the David and Bentall groups, respectively. Ten-year Kaplan-Meier survival was 66% (95% confidence interval: 51% to 77%) for the entire cohort, with 98% (95% confidence interval: 84% to 99%) survival in the David group and 57% (95% confidence interval: 42% to 70%) survival in the Bentall group. Both the David and Bentall procedures are appropriate surgical approaches for aortic root replacement in select patients with an acute type A aortic dissection. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  8. A variable stiffness joint with electrospun P(VDF-TrFE-CTFE) variable stiffness springs

    NARCIS (Netherlands)

    Carloni, Raffaella; Lapp, Valerie I.; Cremonese, Andrea; Belcari, Juri; Zucchelli, Andrea

    This letter presents a novel rotational variable stiffness joint that relies on one motor and a set of variable stiffness springs. The variable stiffness springs are leaf springs with a layered design, i.e., an electro-active layer of electrospun aligned nanofibers of poly(vinylidene

  9. Wall stress on ascending thoracic aortic aneurysms with bicuspid compared with tricuspid aortic valve.

    Science.gov (United States)

    Xuan, Yue; Wang, Zhongjie; Liu, Raymond; Haraldsson, Henrik; Hope, Michael D; Saloner, David A; Guccione, Julius M; Ge, Liang; Tseng, Elaine

    2018-03-08

    Guidelines for repair of bicuspid aortic valve-associated ascending thoracic aortic aneurysms have been changing, most recently to the same criteria as tricuspid aortic valve-ascending thoracic aortic aneurysms. Rupture/dissection occurs when wall stress exceeds wall strength. Recent studies suggest similar strength of bicuspid aortic valve versus tricuspid aortic valve-ascending thoracic aortic aneurysms; thus, comparative wall stress may better predict dissection in bicuspid aortic valve versus tricuspid aortic valve-ascending thoracic aortic aneurysms. Our aim was to determine whether bicuspid aortic valve-ascending thoracic aortic aneurysms had higher wall stresses than their tricuspid aortic valve counterparts. Patients with bicuspid aortic valve- and tricuspid aortic valve-ascending thoracic aortic aneurysms (bicuspid aortic valve = 17, tricuspid aortic valve = 19) greater than 4.5 cm underwent electrocardiogram-gated computed tomography angiography. Patient-specific 3-dimensional geometry was reconstructed and loaded to systemic pressure after accounting for prestress geometry. Finite element analyses were performed using the LS-DYNA solver (LSTC Inc, Livermore, Calif) with user-defined fiber-embedded material model to determine ascending thoracic aortic aneurysm wall stress. Bicuspid aortic valve-ascending thoracic aortic aneurysms 99th-percentile longitudinal stresses were 280 kPa versus 242 kPa (P = .028) for tricuspid aortic valve-ascending thoracic aortic aneurysms in systole. These stresses did not correlate to diameter for bicuspid aortic valve-ascending thoracic aortic aneurysms (r = -0.004) but had better correlation to tricuspid aortic valve-ascending thoracic aortic aneurysms diameter (r = 0.677). Longitudinal stresses on sinotubular junction were significantly higher in bicuspid aortic valve-ascending thoracic aortic aneurysms than in tricuspid aortic valve-ascending thoracic aortic aneurysms (405 vs 329 kPa, P = .023). Bicuspid

  10. Load to Failure and Stiffness

    Science.gov (United States)

    Esquivel, Amanda O.; Duncan, Douglas D.; Dobrasevic, Nikola; Marsh, Stephanie M.; Lemos, Stephen E.

    2015-01-01

    Background: Rotator cuff tendinopathy is a frequent cause of shoulder pain that can lead to decreased strength and range of motion. Failures after using the single-row technique of rotator cuff repair have led to the development of the double-row technique, which is said to allow for more anatomical restoration of the footprint. Purpose: To compare 5 different types of suture patterns while maintaining equality in number of anchors. The hypothesis was that the Mason-Allen–crossed cruciform transosseous-equivalent technique is superior to other suture configurations while maintaining equality in suture limbs and anchors. Study Design: Controlled laboratory study. Methods: A total of 25 fresh-frozen cadaveric shoulders were randomized into 5 suture configuration groups: single-row repair with simple stitch technique; single-row repair with modified Mason-Allen technique; double-row Mason-Allen technique; double-row cross-bridge technique; and double-row suture bridge technique. Load and displacement were recorded at 100 Hz until failure. Stiffness and bone mineral density were also measured. Results: There was no significant difference in peak load at failure, stiffness, maximum displacement at failure, or mean bone mineral density among the 5 suture configuration groups (P row rotator cuff repair to be superior to the single-row repair; however, clinical research does not necessarily support this. This study found no difference when comparing 5 different repair methods, supporting research that suggests the number of sutures and not the pattern can affect biomechanical properties. PMID:26665053

  11. Laparo- and thoracoscopic aortic aneurysm neck optimization and treatment of potential endoleaks type IA and II in a porcine model

    DEFF Research Database (Denmark)

    Kloster, Brian Ozeraitis; Lund, Lars; Lindholt, Jes S.

    2016-01-01

    , externally placed collars/aneuwraps around the proximal AAA neck and just below the left subclavian artery and division of the aortic side branches were carried out laparo-and thoracoscopically. Results: For the laparoscopic and thoracoscopic procedures respectively, mean operative time was 143 ± 41 min...

  12. Endothelial Estrogen Receptor-α Does Not Protect Against Vascular Stiffness Induced by Western Diet in Female Mice.

    Science.gov (United States)

    Manrique, Camila; Lastra, Guido; Ramirez-Perez, Francisco I; Haertling, Dominic; DeMarco, Vincent G; Aroor, Annayya R; Jia, Guanghong; Chen, Dongqing; Barron, Brady J; Garro, Mona; Padilla, Jaume; Martinez-Lemus, Luis A; Sowers, James R

    2016-04-01

    Consumption of a diet high in fat and refined carbohydrates (Western diet [WD]) is associated with obesity and insulin resistance, both major risk factors for cardiovascular disease (CVD). In women, obesity and insulin resistance abrogate the protection against CVD likely afforded by estrogen signaling through estrogen receptor (ER)α. Indeed, WD in females results in increased vascular stiffness, which is independently associated with CVD. We tested the hypothesis that loss of ERα signaling in the endothelium exacerbates WD-induced vascular stiffening in female mice. We used a novel model of endothelial cell (EC)-specific ERα knockout (EC-ERαKO), obtained after sequential crossing of the ERα double floxed mice and VE-Cadherin Cre-recombinase mice. Ten-week-old females, EC-ERαKO and aged-matched genopairs were fed either a regular chow diet (control diet) or WD for 8 weeks. Vascular stiffness was measured in vivo by pulse wave velocity and ex vivo in aortic explants by atomic force microscopy. In addition, vascular reactivity was assessed in isolated aortic rings. Initial characterization of the model fed a control diet did not reveal changes in whole-body insulin sensitivity, aortic vasoreactivity, or vascular stiffness in the EC-ERαKO mice. Interestingly, ablation of ERα in ECs reduced WD-induced vascular stiffness and improved endothelial-dependent dilation. In the setting of a WD, endothelial ERα signaling contributes to vascular stiffening in females. The precise mechanisms underlying the detrimental effects of endothelial ERα in the setting of a WD remain to be elucidated.

  13. PROXIMITY MANAGEMENT IN CRISIS CONDITIONS

    Directory of Open Access Journals (Sweden)

    Ion Dorin BUMBENECI

    2010-01-01

    Full Text Available The purpose of this study is to evaluate the level of assimilation for the terms "Proximity Management" and "Proximity Manager", both in the specialized literature and in practice. The study has two parts: the theoretical research of the two terms, and an evaluation of the use of Proximity management in 32 companies in Gorj, Romania. The object of the evaluation resides in 27 companies with less than 50 employees and 5 companies with more than 50 employees.

  14. Bovine aortic arch: A novel association with thoracic aortic dilation

    International Nuclear Information System (INIS)

    Malone, C.D.; Urbania, T.H.; Crook, S.E.S.; Hope, M.D.

    2012-01-01

    Aim: To investigate whether there is a link between bovine arch and thoracic aortic aneurysm. Materials and methods: Computed tomography (CT) and magnetic resonance imaging (MRI) images of the thorax of 191 patients with dilated thoracic aortas and 391 consecutive, unselected patients as controls were retrospectively reviewed. Bovine arch was considered present if either a shared origin of the left common carotid and innominate arteries or an origin of the left common carotid from the innominate artery was identified. A chi-square test was used to evaluate the significance of differences between subgroups. Results: A trend towards increased prevalence of bovine arch was seen in patients with dilated aortas (26.2%) compared to controls (20.5%, p = 0.12). The association was statistically significant in patients over 70 years old (31.9%, p = 0.019) and when dilation involved the aortic arch (47.6%, p = 0.003). Conclusions: An association between bovine arch and aortic dilation is seen in older patients, and when dilation involves the aortic arch. Bovine arch should be considered a potential risk factor for thoracic aortic aneurysm.

  15. Acute Right Coronary Ostial Stenosis during Aortic Valve Replacement

    Directory of Open Access Journals (Sweden)

    Sarwar Umran

    2012-01-01

    Full Text Available We report a rare case of acute right coronary artery stenosis developing in a patient undergoing aortic valve replacement. We present a case report with a brief overview of the literature relating to coronary artery occlusion associated with cardiac valve surgery - the theories and treatments are discussed. A 85 year-old female was admitted under the care of the cardiothoracic team with signs and symptoms of heart failure. Investigations, including cardiac echocardiography and coronary angiography, indicated a critical aortic valve stenosis. Intraoperative right ventricular failure ensued post aortic valve replacement. Subsequent investigations revealed an acute occlusion of the proximal right coronary artery with resultant absence of distal flow supplying the right ventricle. An immediate right coronary artery bypass procedure was performed with resolution of the right ventricular failure. Subsequent weaning off cardiopulmonary bypass was uneventful and the patient continued to make excellent recovery in the postoperative phase. To our knowledge this is one of the few documented cases of intraoperative acute coronary artery occlusion developing during valve surgery. However, surgeons should be aware of the potential for acute occlusion so that early recognition and rapid intervention can be instituted.

  16. Endoluminal treatment of aortic dissection

    Energy Technology Data Exchange (ETDEWEB)

    Chavan, Ajay; Lotz, Joachim; Galanski, Michael [Department of Diagnostic Radiology, Hannover Medical School, Carl Neuberg Strasse 1, 30625, Hannover (Germany); Oelert, Frank; Haverich, Axel; Karck, Matthias [Department of Thoracic and Cardiovascular Surgery, Hannover Medical School, Carl Neuberg Strasse 1, 30625, Hannover (Germany)

    2003-11-01

    Aortic dissection is most often a catastrophic medical emergency which, if untreated, can be potentially fatal. The intention of therapy in patients with aortic dissection is to prevent aortic rupture or aneurysm formation as well as to relieve branch vessel ischaemia. Patients with aortic dissection are often poor candidates for anaesthesia and surgery and the surgical procedure itself is challenging requiring thoracotomy, aortic cross clamping, blood transfusion as well as prolonged hospital stay in some cases. Operative mortality is especially high in patients with critical mesenteric or renal ischaemia. The past decade has experienced the emergence of a number of interventional radiological or minimally invasive techniques which have significantly improved the management of patients with aortic dissection. These include stent grafting for entry site closure to prevent aneurysmatic widening of the false lumen as well as percutaneous techniques such as balloon fenestration of the intimal flap and aortic true lumen stenting to alleviate branch vessel ischaemia. False lumen thrombosis following entry closure with stent grafts has been observed in 86-100% of patients, whereas percutaneous interventions are able to effectively relieve organ ischaemia in approximately 90% of the cases. In the years to come, it is to be expected that these endoluminal techniques will become the method of choice for treating most type-B dissections and will assist in significantly reducing the number of open surgical procedures required for type-A dissections. The intention of this article is to provide an overview of the current status of these endoluminal techniques based on our own experience as well as on a review of the relevant literature. (orig.)

  17. Endoluminal treatment of aortic dissection

    International Nuclear Information System (INIS)

    Chavan, Ajay; Lotz, Joachim; Galanski, Michael; Oelert, Frank; Haverich, Axel; Karck, Matthias

    2003-01-01

    Aortic dissection is most often a catastrophic medical emergency which, if untreated, can be potentially fatal. The intention of therapy in patients with aortic dissection is to prevent aortic rupture or aneurysm formation as well as to relieve branch vessel ischaemia. Patients with aortic dissection are often poor candidates for anaesthesia and surgery and the surgical procedure itself is challenging requiring thoracotomy, aortic cross clamping, blood transfusion as well as prolonged hospital stay in some cases. Operative mortality is especially high in patients with critical mesenteric or renal ischaemia. The past decade has experienced the emergence of a number of interventional radiological or minimally invasive techniques which have significantly improved the management of patients with aortic dissection. These include stent grafting for entry site closure to prevent aneurysmatic widening of the false lumen as well as percutaneous techniques such as balloon fenestration of the intimal flap and aortic true lumen stenting to alleviate branch vessel ischaemia. False lumen thrombosis following entry closure with stent grafts has been observed in 86-100% of patients, whereas percutaneous interventions are able to effectively relieve organ ischaemia in approximately 90% of the cases. In the years to come, it is to be expected that these endoluminal techniques will become the method of choice for treating most type-B dissections and will assist in significantly reducing the number of open surgical procedures required for type-A dissections. The intention of this article is to provide an overview of the current status of these endoluminal techniques based on our own experience as well as on a review of the relevant literature. (orig.)

  18. Left Ventricular Assist Device Implantation with Concomitant Aortic Valve and Ascending Aortic Replacement.

    Science.gov (United States)

    Huenges, Katharina; Panholzer, Bernd; Cremer, Jochen; Haneya, Assad

    2018-01-01

    Left ventricular assist device (LVAD) is nowadays a routine therapy for patients with advanced heart failure. We present the case of a 74-year-old male patient who was admitted to our center with terminal heart failure in dilated cardiomyopathy and ascending aortic aneurysm with aortic valve regurgitation. The LVAD implantation with simultaneous aortic valve and supracoronary ascending aortic replacement was successfully performed.

  19. Dynamics of the aortic annulus in 4D CT angiography for transcatheter aortic valve implantation patients

    NARCIS (Netherlands)

    Elattar, Mustafa A.; Vink, Leon W.; van Mourik, Martijn S.; Baan, Jan; Vanbavel, Ed T.; Planken, R. Nils; Marquering, Henk A.

    2017-01-01

    Transcatheter aortic valve implantation (TAVI) is a well-established treatment for patients with severe aortic valve stenosis. This procedure requires pre-operative planning by assessment of aortic dimensions on CT Angiography (CTA). It is well-known that the aortic root dimensions vary over the

  20. Stiffness and damping in mechanical design

    National Research Council Canada - National Science Library

    Rivin, Eugene I

    1999-01-01

    ... important conceptual issues are stiffness of mechanical structures and their components and damping in mechanical systems sensitive to and/or generating vibrations. Stiffness and strength are the most important criteria for many mechanical designs. However, although there are hundreds of books on various aspects of strength, and strength issues ar...

  1. Combined open proximal and stent-graft distal repair for distal arch aneurysms: an alternative to total debranching.

    Science.gov (United States)

    Zierer, Andreas; Sanchez, Luis A; Moon, Marc R

    2009-07-01

    We present herein a novel, combined, simultaneous open proximal and stent-graft distal repair for complex distal aortic arch aneurysms involving the descending aorta. In the first surgical step, the transverse arch is opened during selective antegrade cerebral perfusion, and a Dacron graft (DuPont, Wilmington, DE) is positioned down the descending aorta in an elephant trunk-like fashion with its proximal free margin sutured circumferentially to the aorta just distal to the left subclavian or left common carotid artery. With the graft serving as the new proximal landing zone, subsequent endovascular repair is performed antegrade during rewarming through the ascending aorta.

  2. Bicuspid Aortic Valve Disease: A Comprehensive Review

    OpenAIRE

    Mordi, Ify; Tzemos, Nikolaos

    2012-01-01

    Bicuspid aortic valve is the commonest congenital cardiac abnormality in the general population. This paper article will discuss our current knowledge of the anatomy, pathophysiology, genetics, and clinical aspects of bicuspid aortic valve disease.

  3. Aortic compliance in patients with aortic regurgitation. Evaluation with magnetic resonance imaging

    International Nuclear Information System (INIS)

    Murai, Sachiko; Hamada, Seiki; Ueguchi, Takashi

    2005-01-01

    The purpose of this study was to assess by means of cine magnetic resonance imaging (MRI) aortic compliance before and after aortic valve replacement (AVR with SJM (St. Jude Medical, St paul, MN) valve) in patients with aortic regurgitation (AR). Two groups (healthy controls and patients with severe isolated AR) of 10 subjects each were included in this study. Cine MRI was performed at three locations of the aorta, and aortic compliance was calculated by dividing the maximum change in the aortic area by pulse pressure. Cine MRI is useful to assess abnormalities of aortic compliance in patients with AR. Compared with the control group, aortic compliance in the AR group was significantly less in the ascending aorta (p<0.05), decreasing in order of aortic location. After AVR, aortic compliance improved for all locations. Cine MRI enables assessment of aortic biophysical properties such as a compliance for evaluating the progression of AR and the efficacy of treatment. (author)

  4. Abdominal aortic feminism.

    Science.gov (United States)

    Mortimer, Alice Emily

    2014-11-14

    A 79-year-old woman presented to a private medical practice 2 years previously for an elective ultrasound screening scan. This imaging provided the evidence for a diagnosis of an abdominal aortic aneurysm (AAA) to be made. Despite having a number of recognised risk factors for an AAA, her general practitioner at the time did not follow the guidance set out by the private medical professional, that is, to refer the patient to a vascular specialist to be entered into a surveillance programme and surgically evaluated. The patient became symptomatic with her AAA, was admitted to hospital and found to have a tender, symptomatic, 6 cm leaking AAA. She consented for an emergency open AAA repair within a few hours of being admitted to hospital, despite the 50% perioperative mortality risk. The patient spent 4 days in intensive care where she recovered well. She was discharged after a 12 day hospital stay but unfortunately passed away shortly after her discharge from a previously undiagnosed gastric cancer. 2014 BMJ Publishing Group Ltd.

  5. Aortic atresia with normal sized left ventricle

    OpenAIRE

    Priya Jagia; Arun Sharma; Saurabh K Gupta; Munish Guleria

    2016-01-01

    Aortic atresia with an associated ventricular septal defect and adequate sized left ventricle is extremely rare. We present two cases in which an alternate diagnosis was suggested on echocardiography because the hypoplastic aortic trunk was missed due to its small caliber. The final diagnosis was, however, clinched on dual source computed tomography, which not only showed the thin aortic trunk but also clearly depicted the coronary artery origins from the hypoplastic aortic root. To the best ...

  6. A History of Thoracic Aortic Surgery.

    Science.gov (United States)

    McFadden, Paul Michael; Wiggins, Luke M; Boys, Joshua A

    2017-08-01

    Ancient historical texts describe the presence of aortic pathology conditions, although the surgical treatment of thoracic aortic disease remained insurmountable until the 19th century. Surgical treatment of thoracic aortic disease then progressed along with advances in surgical technique, conduit production, cardiopulmonary bypass, and endovascular technology. Despite radical advances in aortic surgery, principles established by surgical pioneers of the 19th century hold firm to this day. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Aortic or Mitral Valve Replacement With the Biocor and Biocor Supra

    Science.gov (United States)

    2017-04-26

    Aortic Valve Insufficiency; Aortic Valve Regurgitation; Aortic Valve Stenosis; Aortic Valve Incompetence; Mitral Valve Insufficiency; Mitral Valve Regurgitation; Mitral Valve Stenosis; Mitral Valve Incompetence

  8. Favorable effects on arterial stiffness after renal sympathetic denervation for the treatment of resistant hypertension: a cardiovascular magnetic resonance study

    Directory of Open Access Journals (Sweden)

    Hammer TA

    2016-09-01

    Full Text Available Tommy Arild Hammer,1 Knut Asbjørn Rise Langlo,2 Pål Erik Goa,1,3 Fadl Elmula M Fadl Elmula,4,5 Pavel Hoffmann,6 Knut Haakon Stensaeth1,7 1Department of Radiology and Nuclear Medicine, 2Department of Nephrology, St Olav’s University Hospital, Trondheim, Norway; 3Department of Physics, Norwegian University of Science and Technology, Trondheim, Norway; 4Institute of Cardiovascular and Renal Research, Department of Cardiology, Oslo University Hospital, Oslo, Norway; 5Faculty of Clinical Medicine, University of Oslo, Oslo, Norway; 6Department of Cardiology, Oslo University Hospital, Oslo, Norway; 7Institute of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway Aims: Renal sympathetic denervation (RDN has recently been suggested to be a novel treatment strategy for patients with treatment-resistant hypertension. However, the latest randomized studies have provided conflicting results and the influence of RDN on arterial stiffness remains unclear. Therefore, this study aimed to detect the effects of RDN on arterial stiffness as measured with aortic pulse wave velocity (PWV and distensibility in addition to cardiac function and T1 mapping at baseline and at 6-month follow-up.Methods: RDN was performed in a total of 16 patients with treatment-resistant hypertension, and the procedures were conducted at two university hospitals using two different RDN devices. All patients and age-matched controls underwent a comprehensive clinical examination and cardiac magnetic resonance protocols both at baseline and at a 6-month follow-up.Results: In the treatment group, the systolic blood pressure (SBP was found to be decreased at the follow-up visit (office SBP; 173±24 compared to 164±25 mmHg [P= 0.033], the 24-hour ambulatory SBP had decreased (163±25 compared to 153±20 mmHg [P=0.057], the aortic PWV had decreased from 8.24±3.34 to 6.54±1.31 m/s (P=0.053, and the aortic distensibility had increased from 2

  9. Rotational stiffness of American football shoes affects ankle biomechanics and injury severity.

    Science.gov (United States)

    Button, Keith D; Braman, Jerrod E; Davison, Mark A; Wei, Feng; Schaeffer, Maureen C; Haut, Roger C

    2015-06-01

    While previous studies have investigated the effect of shoe-surface interaction on injury risk, few studies have examined the effect of rotational stiffness of the shoe. The hypothesis of the current study was that ankles externally rotated to failure in shoes with low rotational stiffness would allow more talus eversion than those in shoes with a higher rotational stiffness, resulting in less severe injury. Twelve (six pairs) cadaver lower extremities were externally rotated to gross failure while positioned in 20 deg of pre-eversion and 20 deg of predorsiflexion by fixing the distal end of the foot, axially loading the proximal tibia, and internally rotating the tibia. One ankle in each pair was constrained by an American football shoe with a stiff upper, while the other was constrained by an American football shoe with a flexible upper. Experimental bone motions were input into specimen-specific computational models to examine levels of ligament elongation to help understand mechanisms of ankle joint failure. Ankles in flexible shoes allowed 6.7±2.4 deg of talus eversion during rotation, significantly greater than the 1.7±1.0 deg for ankles in stiff shoes (p = 0.01). The significantly greater eversion in flexible shoes was potentially due to a more natural response of the ankle during rotation, possibly affecting the injuries that were produced. All ankles failed by either medial ankle injury or syndesmotic injury, or a combination of both. Complex (more than one ligament or bone) injuries were noted in 4 of 6 ankles in stiff shoes and 1 of 6 ankles in flexible shoes. Ligament elongations from the computational model validated the experimental injury data. The current study suggested flexibility (or rotational stiffness) of the shoe may play an important role in both the severity of ankle injuries for athletes.

  10. Surgical treatment of Marfan patients with aneurysms and dissection of the proximal aorta.

    Science.gov (United States)

    Mingke, D; Dresler, C; Pethig, K; Heinemann, M; Borst, H G

    1998-02-01

    The authors retrospectively analyzed early and late results of surgical treatment for 79 Marfan patients with aneurysms and dissection of the proximal aorta. From September 1979 to February 1996, 79 patients with Marfan syndrome underwent aortic root replacement using composite grafts (n=68, Bentall-technique 63, button-technique 5), and ascending aortic replacement with a valve-sparing procedure (n=11). There were 12 patients (15.2%) who simultaneously received partial or total arch replacement. 55 patients (69.6%) were male, and 24 female (30.4%). The average age was 33.8 years. Forty-one patient (51.9%) had non-dissecting aneurysms while the remaining 38 patients suffered from either acute (24.0%) or chronic aortic dissection (24.0%). The aortic valve was involved in 97.5% of all cases. The total early mortality (valve-sparing operation and in those with chronic aortic dissection. The follow-up rate was 98.7%. During a mean follow-up of 68+/-25 months 10 patients (13.3%) died and cardiac complications were a common cause of the late deaths. There was no late mortality in the valve-sparing operations during a mean follow-up period of 8+/-6 months, however, 1 required valve replacement. 19 (25.3%) of the 75 patients surviving late have undergone 25 secondary operations on the cardiovascular system. Reoperations at aortic sites distant from the original were much more frequent after primary repair for acute and chronic dissection when compared to non-dissecting aneurysms (pMarfan-patients with non-dissecting and dissecting aneurysms of the aortic root. Our early experience in 11 patients with valve-sparing procedures indicated that this,variant may be the better choice in selected patients.

  11. Topology optimization under stochastic stiffness

    Science.gov (United States)

    Asadpoure, Alireza

    Topology optimization is a systematic computational tool for optimizing the layout of materials within a domain for engineering design problems. It allows variation of structural boundaries and connectivities. This freedom in the design space often enables discovery of new, high performance designs. However, solutions obtained by performing the optimization in a deterministic setting may be impractical or suboptimal when considering real-world engineering conditions with inherent variabilities including (for example) variabilities in fabrication processes and operating conditions. The aim of this work is to provide a computational methodology for topology optimization in the presence of uncertainties associated with structural stiffness, such as uncertain material properties and/or structural geometry. Existing methods for topology optimization under deterministic conditions are first reviewed. Modifications are then proposed to improve the numerical performance of the so-called Heaviside Projection Method (HPM) in continuum domains. Next, two approaches, perturbation and Polynomial Chaos Expansion (PCE), are proposed to account for uncertainties in the optimization procedure. These approaches are intrusive, allowing tight and efficient coupling of the uncertainty quantification with the optimization sensitivity analysis. The work herein develops a robust topology optimization framework aimed at reducing the sensitivity of optimized solutions to uncertainties. The perturbation-based approach combines deterministic topology optimization with a perturbation method for the quantification of uncertainties. The use of perturbation transforms the problem of topology optimization under uncertainty to an augmented deterministic topology optimization problem. The PCE approach combines the spectral stochastic approach for the representation and propagation of uncertainties with an existing deterministic topology optimization technique. The resulting compact representations

  12. Complex atheromatosis of the aortic arch in cerebral infarction.

    Science.gov (United States)

    Capmany, Ramón Pujadas; Ibañez, Montserrat Oliveras; Pesquer, Xavier Jané

    2010-08-01

    In many stroke patients it is not possible to establish the etiology of stroke. However, in the last two decades, the use of transesophageal echocardiography in patients with stroke of uncertain etiology reveals atherosclerotic plaques in the aortic arch, which often protrude into the lumen and have mobile components in a high percentage of cases. Several autopsy series and retrospective studies of cases and controls have shown an association between aortic arch atheroma and arterial embolism, which was later confirmed by prospectively designed studies. The association with ischemic stroke was particularly strong when atheromas were located proximal to the ostium of the left subclavian artery, when the plaque was ≥ 4 mm thick and particularly when mobile components are present. In these cases, aspirin might not prevent adequately new arterial ischemic events especially stroke. Here we review the evidence of aortic arch atheroma as an independent risk factor for stroke and arterial embolism, including clinical and pathological data on atherosclerosis of the thoracic aorta as an embolic source. In addition, the impact of complex plaques (≥ 4 mm thick, or with mobile components) on increasing the risk of stroke is also reviewed. In non-randomized retrospective studies anticoagulation was superior to antiplatelet therapy in patients with stroke and aortic arch plaques with mobile components. In a retrospective case-control study, statins significantly reduced the relative risk of new vascular events. However, given the limited data available and its retrospective nature, randomized prospective studies are needed to establish the optimal secondary prevention therapeutic regimens in these high risk patients.

  13. Free-weight resistance exercise on pulse wave reflection and arterial stiffness between sexes in young, resistance-trained adults.

    Science.gov (United States)

    Kingsley, J Derek; Tai, Yu Lun; Mayo, Xian; Glasgow, Alaina; Marshall, Erica

    2017-09-01

    We sought to determine the sex-specific effects of an acute bout of free-weight resistance exercise (RE) on pulse wave reflection (aortic blood pressures, augmentation index (AIx), AIx at 75 bpm (AIx@75), augmentation pressure (AP), time of the reflected wave (Tr), subendocardial viability ratio (SEVR)), and aortic arterial stiffness in resistance-trained individuals. Resistance-trained men (n = 14) and women (n = 12) volunteered to participate in the study. Measurements were taken in the supine position at rest, and 10 minutes after 3 sets of 10 repetitions at 75% 1-repetition maximum on the squat, bench press, and deadlift. A 2 × 2 × 2 ANOVA was used to analyse the effects of sex (men, women) across condition (RE, control) and time (rest, recovery). There were no differences between sexes across conditions and time. There was no effect of the RE on brachial or aortic blood pressures. There were significant condition × time interactions for AIx (rest: 12.1 ± 7.9%; recovery: 19.9 ± 10.5%, p = .003), AIx@75 (rest: 5.3 ± 7.9%; recovery: 24.5 ± 14.3%, p = .0001), AP (rest: 4.9 ± 2.8 mmHg; recovery: 8.3 ± 6.0 mmHg, p = .004), and aortic arterial stiffness (rest: 5.3 ± 0.6 ms; recovery: 5.9 ± 0.7 ms, p = .02) with significant increases during recovery from the acute RE. There was also a significant condition × time for time of the reflected wave (rest: 150 ± 7 ms; recovery: 147 ± 9 ms, p = .02) and SEVR (rest: 147 ± 17%; recovery: 83 ± 24%, p = .0001) such that they were reduced during recovery from the acute RE compared to the control. These data suggest that an acute bout of RE increases AIx, AIx@75, and aortic arterial stiffness similarly between men and women without significantly altering aortic blood pressures.

  14. Hybrid Approach of Aortic Diseases: Zone 1 Delivery and Volumetric Analysis on the Descending Aorta

    Directory of Open Access Journals (Sweden)

    José Augusto Duncan

    Full Text Available Abstract Introduction: Conventional techniques of surgical correction of arch and descending aortic diseases remains as high-risk procedures. Endovascular treatments of abdominal and descending thoracic aorta have lower surgical risk. Evolution of both techniques - open debranching of the arch and endovascular approach of the descending aorta - may extend a less invasive endovascular treatment for a more extensive disease with necessity of proximal landing zone in the arch. Objective: To evaluate descending thoracic aortic remodeling by means of volumetric analysis after hybrid approach of aortic arch debranching and stenting the descending aorta. Methods: Retrospective review of seven consecutive patients treated between September 2014 and August 2016 for diseases of proximal descending aorta (aneurysms and dissections by hybrid approach to deliver the endograft at zone 1. Computed tomography angiography were analyzed using a specific software to calculate descending thoracic aorta volumes pre- and postoperatively. Results: Follow-up was done in 100% of patients with a median time of 321 days (range, 41-625 days. No deaths or permanent neurological complications were observed. There were no endoleaks or stent migrations. Freedom from reintervention was 100% at 300 days and 66% at 600 days. Median volume reduction was of 45.5 cm3, representing a median volume shrinkage by 9.3%. Conclusion: Hybrid approach of arch and descending thoracic aorta diseases is feasible and leads to a favorable aortic remodeling with significant volume reduction.

  15. Real chimney technique for total debranching of supra-aortic trunks.

    Science.gov (United States)

    Kato, Masaaki; Kagaya, Hideo; Kubo, Yoji; Banno, Hiroshi; Ohkubo, Nobukazu

    2015-02-01

    Side-clamping of the ascending aorta is an indispensable technique for proximal anastomosis in total debranching of supra-aortic trunks and in endovascular aneurysm repair for arch aneurysm. However, this procedure may lead to the dislodging of multiple plaques and to clamp injury of the ascending aorta. We developed a clampless technique to achieve proximal anastomosis between the ascending aorta and an artificial graft used for total debranching of supra-aortic trunks. We applied this method in six patients with arch aneurysm and a plaque-rich ascending aorta and were able to achieve total debranching of the supra-aortic trunks in all of the patients without side-clamping the ascending aorta and no procedurally related complications. This clampless anastomosis technique ("real chimney technique") in the ascending aorta is a valuable option for total debranching of supra-aortic trunks in the hybrid repair of arch aneurysms. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  16. Observer-Based Human Knee Stiffness Estimation.

    Science.gov (United States)

    Misgeld, Berno J E; Luken, Markus; Riener, Robert; Leonhardt, Steffen

    2017-05-01

    We consider the problem of stiffness estimation for the human knee joint during motion in the sagittal plane. The new stiffness estimator uses a nonlinear reduced-order biomechanical model and a body sensor network (BSN). The developed model is based on a two-dimensional knee kinematics approach to calculate the angle-dependent lever arms and the torques of the muscle-tendon-complex. To minimize errors in the knee stiffness estimation procedure that result from model uncertainties, a nonlinear observer is developed. The observer uses the electromyogram (EMG) of involved muscles as input signals and the segmental orientation as the output signal to correct the observer-internal states. Because of dominating model nonlinearities and nonsmoothness of the corresponding nonlinear functions, an unscented Kalman filter is designed to compute and update the observer feedback (Kalman) gain matrix. The observer-based stiffness estimation algorithm is subsequently evaluated in simulations and in a test bench, specifically designed to provide robotic movement support for the human knee joint. In silico and experimental validation underline the good performance of the knee stiffness estimation even in the cases of a knee stiffening due to antagonistic coactivation. We have shown the principle function of an observer-based approach to knee stiffness estimation that employs EMG signals and segmental orientation provided by our own IPANEMA BSN. The presented approach makes realtime, model-based estimation of knee stiffness with minimal instrumentation possible.

  17. Big bang nucleosynthesis with a stiff fluid

    International Nuclear Information System (INIS)

    Dutta, Sourish; Scherrer, Robert J.

    2010-01-01

    Models that lead to a cosmological stiff fluid component, with a density ρ S that scales as a -6 , where a is the scale factor, have been proposed recently in a variety of contexts. We calculate numerically the effect of such a stiff fluid on the primordial element abundances. Because the stiff fluid energy density decreases with the scale factor more rapidly than radiation, it produces a relatively larger change in the primordial helium-4 abundance than in the other element abundances, relative to the changes produced by an additional radiation component. We show that the helium-4 abundance varies linearly with the density of the stiff fluid at a fixed fiducial temperature. Taking ρ S10 and ρ R10 to be the stiff fluid energy density and the standard density in relativistic particles, respectively, at T=10 MeV, we find that the change in the primordial helium abundance is well-fit by ΔY p =0.00024(ρ S10 /ρ R10 ). The changes in the helium-4 abundance produced by additional radiation or by a stiff fluid are identical when these two components have equal density at a 'pivot temperature', T * , where we find T * =0.55 MeV. Current estimates of the primordial 4 He abundance give the constraint on a stiff fluid energy density of ρ S10 /ρ R10 <30.

  18. Dynamic stiffness of suction caissons - vertical vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Ibsen, Lars Bo; Liingaard, M.; Andersen, Lars

    2006-12-15

    The dynamic response of offshore wind turbines are affected by the properties of the foundation and the subsoil. The purpose of this report is to evaluate the dynamic soil-structure interaction of suction caissons for offshore wind turbines. The investigation is limited to a determination of the vertical dynamic stiffness of suction caissons. The soil surrounding the foundation is homogenous with linear viscoelastic properties. The dynamic stiffness of the suction caisson is expressed by dimensionless frequency-dependent dynamic stiffness coefficients corresponding to the vertical degree of freedom. The dynamic stiffness coefficients for the foundations are evaluated by means of a dynamic three-dimensional coupled Boundary Element/Finite Element model. Comparisons are made with known analytical and numerical solutions in order to evaluate the static and dynamic behaviour of the Boundary Element/Finite Element model. The vertical frequency dependent stiffness has been determined for different combinations of the skirt length, Poisson's ratio and the ratio between soil stiffness and skirt stiffness. Finally the dynamic behaviour at high frequencies is investigated. (au)

  19. Aortic valve bypass surgery in severe aortic valve stenosis: Insights from cardiac and brain magnetic resonance imaging.

    Science.gov (United States)

    Mantini, Cesare; Caulo, Massimo; Marinelli, Daniele; Chiacchiaretta, Piero; Tartaro, Armando; Cotroneo, Antonio Raffaele; Di Giammarco, Gabriele

    2018-04-13

    To investigate and describe the distribution of aortic and cerebral blood flow (CBF) in patients with severe valvular aortic stenosis (AS) before and after aortic valve bypass (AVB) surgery. We enrolled 10 consecutive patients who underwent AVB surgery for severe AS. Cardiovascular magnetic resonance imaging (CMR) and brain magnetic resonance imaging were performed as baseline before surgery and twice after surgery. Quantitative flow measurements were obtained using 1.5-T magnetic resonance imaging (MRI) scanner phase-contrast images of the ascending aorta, descending thoracic aorta (3 cm proximally and distally from the conduit-to-aorta anastomosis), and ventricular outflow portion of the conduit. The evaluation of CBF was performed using 3.0-T MRI scanner arterial spin labeling (ASL) through sequences acquired at the gray matter, dorsal default-mode network, and sensorimotor levels. Conduit flow, expressed as the percentage of total antegrade flow through the conduit, was 63.5 ± 8% and 67.8 ± 7% on early and mid-term postoperative CMR, respectively (P surgery in patients with severe AS, cardiac output is split between the native left ventricular outflow tract and the apico-aortic bypass, with two-thirds of the total antegrade flow passing through the latter and one-third passing through the former. In our experience, CBF assessment confirms that the flow redistribution does not jeopardize cerebral blood supply. Copyright © 2018 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  20. Hybrid Repair of Complex Thoracic Aortic Arch Pathology: Long-Term Outcomes of Extra-anatomic Bypass Grafting of the Supra-aortic Trunk

    International Nuclear Information System (INIS)

    Lotfi, S.; Clough, R. E.; Ali, T.; Salter, R.; Young, C. P.; Bell, R.; Modarai, B.; Taylor, P.

    2013-01-01

    Hybrid repair constitutes supra-aortic debranching before thoracic endovascular aortic repair (TEVAR). It offers improved short-term outcome compared with open surgery; however, longer-term studies are required to assess patient outcomes and patency of the extra-anatomic bypass grafts. A prospectively maintained database of 380 elective and urgent patients who had undergone TEVAR (1997–2011) was analyzed retrospectively. Fifty-one patients (34 males; 17 females) underwent hybrid repair. Median age was 71 (range, 18–90) years with mean follow-up of 15 (range, 0–61) months. Perioperative complications included death: 10 % (5/51), stroke: 12 % (6/51), paraplegia: 6 % (3/51), endoleak: 16 % (8/51), rupture: 4 % (2/51), upper-limb ischemia: 2 % (1/51), bypass graft occlusion: 4 % (2/51), and cardiopulmonary complications in 14 % (7/51). Three patients (6 %) required emergency intervention for retrograde dissection: (2 aortic root repairs; 2 innominate stents). Early reintervention was performed for type 1 endoleak in two patients (2 proximal cuff extensions). One patient underwent innominate stenting and revision of their bypass for symptomatic restenosis. At 48 months, survival was 73 %. Endoleak was detected in three (6 %) patients (type 1 = 2; type 2 = 1) requiring debranching with proximal stent graft (n = 2) and proximal extension cuff (n = 1). One patient had a fatal rupture of a mycotic aneurysm and two arch aneurysms expanded. No bypass graft occluded after the perioperative period. Hybrid operations to treat aortic arch disease can be performed with results comparable to open surgery. The longer-term outcomes demonstrate low rates of reintervention and high rates of graft patency.

  1. Hybrid Repair of Complex Thoracic Aortic Arch Pathology: Long-Term Outcomes of Extra-anatomic Bypass Grafting of the Supra-aortic Trunk

    Energy Technology Data Exchange (ETDEWEB)

    Lotfi, S., E-mail: shamim.lotfi@kcl.ac.uk; Clough, R. E.; Ali, T. [Guy' s and St. Thomas' NHS Trust, Vascular Surgery (United Kingdom); Salter, R. [Guy' s and St. Thomas' NHS Trust, Interventional Radiology (United Kingdom); Young, C. P. [Guy' s and St. Thomas' NHS Trust, Cardiac Surgery (United Kingdom); Bell, R.; Modarai, B.; Taylor, P., E-mail: peter.taylor@gstt.nhs.uk [Guy' s and St. Thomas' NHS Trust, Vascular Surgery (United Kingdom)

    2013-02-15

    Hybrid repair constitutes supra-aortic debranching before thoracic endovascular aortic repair (TEVAR). It offers improved short-term outcome compared with open surgery; however, longer-term studies are required to assess patient outcomes and patency of the extra-anatomic bypass grafts. A prospectively maintained database of 380 elective and urgent patients who had undergone TEVAR (1997-2011) was analyzed retrospectively. Fifty-one patients (34 males; 17 females) underwent hybrid repair. Median age was 71 (range, 18-90) years with mean follow-up of 15 (range, 0-61) months. Perioperative complications included death: 10 % (5/51), stroke: 12 % (6/51), paraplegia: 6 % (3/51), endoleak: 16 % (8/51), rupture: 4 % (2/51), upper-limb ischemia: 2 % (1/51), bypass graft occlusion: 4 % (2/51), and cardiopulmonary complications in 14 % (7/51). Three patients (6 %) required emergency intervention for retrograde dissection: (2 aortic root repairs; 2 innominate stents). Early reintervention was performed for type 1 endoleak in two patients (2 proximal cuff extensions). One patient underwent innominate stenting and revision of their bypass for symptomatic restenosis. At 48 months, survival was 73 %. Endoleak was detected in three (6 %) patients (type 1 = 2; type 2 = 1) requiring debranching with proximal stent graft (n = 2) and proximal extension cuff (n = 1). One patient had a fatal rupture of a mycotic aneurysm and two arch aneurysms expanded. No bypass graft occluded after the perioperative period. Hybrid operations to treat aortic arch disease can be performed with results comparable to open surgery. The longer-term outcomes demonstrate low rates of reintervention and high rates of graft patency.

  2. Aortic atresia with normal sized left ventricle

    Directory of Open Access Journals (Sweden)

    Priya Jagia

    2016-01-01

    Full Text Available Aortic atresia with an associated ventricular septal defect and adequate sized left ventricle is extremely rare. We present two cases in which an alternate diagnosis was suggested on echocardiography because the hypoplastic aortic trunk was missed due to its small caliber. The final diagnosis was, however, clinched on dual source computed tomography, which not only showed the thin aortic trunk but also clearly depicted the coronary artery origins from the hypoplastic aortic root. To the best of our knowledge, use of multi-detector computed tomography in aortic atresia with well developed left ventricle has not been reported in literature till date.

  3. MMP-2 Isoforms in Aortic Tissue and Serum of Patients with Ascending Aortic Aneurysms and Aortic Root Aneurysms

    Science.gov (United States)

    Tscheuschler, Anke; Meffert, Philipp; Beyersdorf, Friedhelm; Heilmann, Claudia; Kocher, Nadja; Uffelmann, Xenia; Discher, Philipp; Siepe, Matthias; Kari, Fabian A.

    2016-01-01

    Objective The need for biological markers of aortic wall stress and risk of rupture or dissection of ascending aortic aneurysms is obvious. To date, wall stress cannot be related to a certain biological marker. We analyzed aortic tissue and serum for the presence of different MMP-2 isoforms to find a connection between serum and tissue MMP-2 and to evaluate the potential of different MMP-2 isoforms as markers of high wall stress. Methods Serum and aortic tissue from n = 24 patients and serum from n = 19 healthy controls was analyzed by ELISA and gelatin zymography. 24 patients had ascending aortic aneurysms, 10 of them also had aortic root aneurysms. Three patients had normally functioning valves, 12 had regurgitation alone, eight had regurgitation and stenosis and one had only stenosis. Patients had bicuspid and tricuspid aortic valves (9/15). Serum samples were taken preoperatively, and the aortic wall specimen collected during surgical aortic repair. Results Pro-MMP-2 was identified in all serum and tissue samples. Pro-MMP-2 was detected in all tissue and serum samples from patients with ascending aortic/aortic root aneurysms, irrespective of valve morphology or other clinical parameters and in serum from healthy controls. We also identified active MMP-2 in all tissue samples from patients with ascending aortic/aortic root aneurysms. None of the analyzed serum samples revealed signals relatable to active MMP-2. No correlation between aortic tissue total MMP-2 or tissue pro-MMP-2 or tissue active MMP-2 and serum MMP-2 was found and tissue MMP-2/pro-MMP-2/active MMP-2 did not correlate with aortic diameter. This evidence shows that pro-MMP-2 is the predominant MMP-2 species in serum of patients and healthy individuals and in aneurysmatic aortic tissue, irrespective of aortic valve configuration. Active MMP-2 species are either not released into systemic circulation or not detectable in serum. There is no reliable connection between aortic tissue—and serum MMP-2

  4. Outcomes of Endovascular Abdominal Aortic Aneurysm Repair in Patients with Hostile Neck Anatomy

    International Nuclear Information System (INIS)

    Choke, Edward; Munneke, Graham; Morgan, Robert; Belli, Anna-Maria; Loftus, Ian; McFarland, Robert; Loosemore, Thomas; Thompson, Matthew M.

    2006-01-01

    Purpose. The principal anatomic contraindication to endovascular aneurysm repair (EVR) is an unfavorable proximal aortic neck. With increasing experience, a greater proportion of patients with unfavorable neck anatomy are being offered EVR. This study aimed to evaluate outcomes in patients with challenging proximal aortic neck anatomy. Methods. Prospectively collected data from 147 consecutive patients who underwent EVR between December 1997 and April 2005 were supplemented with a retrospective review of medical records and radiological images. Unfavorable anatomic features were defined as neck diameter >28 mm, angulation >60 deg., circumferential thrombus >50%, and length 30 days) (p = 0.57), distal type I endoleak (p = 0.40), type III endoleak (p 0.51), secondary interventions (p = 1.0), aneurysm sac expansion (p = 0.44), or 30 day mortality (p = 0.70). The good neck group had a significantly increased incidence of type II endoleak (p = 0.023). By multivariate analysis, the incidence of intraoperative adjunctive procedures was significantly increased in the presence of severe angulation (p = 0.041, OR 3.08, 95% CI 1.05-9.04). Conclusion. Patients with severely hostile proximal aortic neck anatomy may be treated with EVR, although severely angulated necks require additional intraoperative procedures. Early outcomes are encouraging and suggest that indications for EVR may be expanded to include patients with hostile neck anatomy

  5. The Effect of Aortic Compliance on Left Ventricular Power Requirement

    Science.gov (United States)

    Pahlevan, Niema; Gharib, Morteza

    2009-11-01

    Aortic compliance depends on both geometry and mechanical properties of the aorta. Reduction in arterial compliance has been associated with aging, smoking, and multiple cardiovascular diseases. Increased stiffness of the aorta affects the wave dynamics in the aorta by increasing both pulse pressure amplitude and wave speed. We hypothesized that decreased aortic compliance leads to an increased left ventricular power requirement for a fixed cardiac output due to altered pulse pressure and pulse wave velocity. We used a computational approach using the finite element method for solid and fluid domains coupled to each other by using the direct coupling method. A nonlinear material model was used for the solid wall. The fluid flow model was considered to be Newtonian, incompressible, and laminar. The simulation was performed for a heart rate of 75 beats per minute for six different compliances while keeping the cardiac output and the peripheral resistance constant. The results show a trend towards increased left ventricular energy expenditure per cycle with decreased compliance. The relevance of these findings to clinical observations will be discussed.

  6. ProxImaL: efficient image optimization using proximal algorithms

    KAUST Repository

    Heide, Felix; Diamond, Steven; Nieß ner, Matthias; Ragan-Kelley, Jonathan; Heidrich, Wolfgang; Wetzstein, Gordon

    2016-01-01

    domain-specific language and compiler for image optimization problems that makes it easy to experiment with different problem formulations and algorithm choices. The language uses proximal operators as the fundamental building blocks of a variety

  7. Aortic Root Enlargement or Sutureless Valve Implantation?

    Directory of Open Access Journals (Sweden)

    Nikolaos G. Baikoussis

    2016-11-01

    Full Text Available Aortic valve replacement (AVR in patients with a small aortic annulus is a challenging issue. The importance of prosthesis–patient mismatch (PPM post aortic valve replacement (AVR is controversial but has to be avoided. Many studies support the fact that PPM has a negative impact on short and long term survival. In order to avoid PPM, aortic root enlargement may be performed. Alternatively and keeping in mind that often some comorbidities are present in old patients with small aortic root, the Perceval S suturelles valve implantation could be a perfect solution. The Perceval sutureless bioprosthesis provides reasonable hemodynamic performance avoiding the PPM and providing the maximum of aortic orifice area. We would like to see in the near future the role of the aortic root enlargement techniques in the era of surgical implantation of the sutureless valve (SAVR and the transcatheter valve implantation (TAVI.

  8. Aortic valve function after bicuspidization of the unicuspid aortic valve.

    Science.gov (United States)

    Aicher, Diana; Bewarder, Moritz; Kindermann, Michael; Abdul-Khalique, Hashim; Schäfers, Hans-Joachim

    2013-05-01

    Unicuspid aortic valve (UAV) anatomy leads to dysfunction of the valve in young individuals. We introduced a reconstructive technique of bicuspidizing the UAV. Initially we copied the typical asymmetry of a normal bicuspid aortic valve (BAV) (I), later we created a symmetric BAV (II). This study compared the hemodynamic function of the two designs of a bicuspidized UAV. Aortic valve function was studied at rest and during exercise in 28 patients after repair of UAV (group I, n = 8; group II, n = 20). There were no differences among the groups I and II with respect to gender, age, body size, or weight. All patients were in New York Heart Association class I. Six healthy adults served as control individuals. All patients were studied with transthoracic echocardiography between 4 and 65 months postoperatively. Systolic gradients were assessed by continuous wave Doppler while patients were at rest and exercising on a bicycle ergometer. Aortic regurgitation was grade I or less in all patients. Resting gradients were significantly elevated in group I compared with group II and control individuals (group I, peak 33.8 ± 7.8 mm Hg; mean 19.1 ± 5.4 mm Hg; group II, peak 15.8 ± 5.4, mean 8.2 ± 2.8 mm Hg; control individuals, peak 6.0 ± 1.6, mean 3.2 ± 0.8 mm Hg; p competence. A symmetric repair design leads to improved systolic aortic valve function at rest and during exercise. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  9. A proximal point algorithm with generalized proximal distances to BEPs

    OpenAIRE

    Bento, G. C.; Neto, J. X. Cruz; Lopes, J. O.; Soares Jr, P. A.; Soubeyran, A.

    2014-01-01

    We consider a bilevel problem involving two monotone equilibrium bifunctions and we show that this problem can be solved by a proximal point method with generalized proximal distances. We propose a framework for the convergence analysis of the sequences generated by the algorithm. This class of problems is very interesting because it covers mathematical programs and optimization problems under equilibrium constraints. As an application, we consider the problem of the stability and change dyna...

  10. Fractures of the proximal humerus

    DEFF Research Database (Denmark)

    Brorson, Stig

    2013-01-01

    Fractures of the proximal humerus have been diagnosed and managed since the earliest known surgical texts. For more than four millennia the preferred treatment was forceful traction, closed reduction, and immobilization with linen soaked in combinations of oil, honey, alum, wine, or cerate......, classification of proximal humeral fractures remains a challenge for the conduct, reporting, and interpretation of clinical trials. The evidence for the benefits of surgery in complex fractures of the proximal humerus is weak. In three systematic reviews I studied the outcome after locking plate osteosynthesis...

  11. Observed variations of monopile foundation stiffness

    DEFF Research Database (Denmark)

    Kallehave, Dan; Thilsted, C.L.; Diaz, Alberto Troya

    2015-01-01

    full-scale measurements obtained from one offshore wind turbine structure located within Horns Reef II offshore wind farm. Data are presented for a 2.5 years period and covers normal operating conditions and one larger storm event. A reduction of the pile-soil stiffness was observed during the storm...... events, followed by a complete regain to a pre-storm level when the storm subsided. In additional, no long term variations of the pile-soil stiffness was observed. The wind turbine is located in dense to very dense sand deposits.......The soil-structure stiffness of monopile foundations for offshore wind turbines has a high impact on the fatigue loading during normal operating conditions. Thus, a robust design must consider the evolution of pile-soil stiffness over the lifetime of the wind farm. This paper present and discuss...

  12. Perioperative management of endovascular abdominal aortic aneurysm repair

    International Nuclear Information System (INIS)

    Wang Haofu; Wang Yuwei; Li Jun; Zhao Zonggang; Qi Sen

    2010-01-01

    Objective: To summarize the clinical experience of perioperative management in performing endovascular abdominal aortic aneurysm repair (EVAR). Methods: EVAR was performed in 22 patients with abdominal aortic aneurysm. The clinical data were retrospectively analyzed. Before treatment the functions of main organs were evaluated and certain measures were adopted in order to protect them. Useful parameters, including the length, diameter, angle and configuration of the proximal and distal aneurysmal neck, the relationship of the aneurysm to aortic branches, the distance from the lowest renal artery to the bifurcation of abdominal aorta, and the quality of access vessels (such as diameter, tortuosity and calcification degree) were determined and assessed with CTA. According to the parameters thus obtained, the suitable stent-graft with ideal diameter and length was selected, and the optimal surgery pattern was employed. Local anesthesia was employed in 20 patients, among them the local anesthesia had to be changed to general anesthesia in one. Epidural anesthesia was carried out in one patient through the surgically-reconstructed iliac artery access,and general anesthesia was employed in one patient who had Stanford type A aortic dissection. The lowest renal artery must be accurately localized before deployment of stent-graft was started. At least one patent internal iliac artery should be reserved when bilateral internal iliac arteries needed to be covered, to be covered by stages or to be reconstructed. After stent-graft placement, angiography must be performed to find out if there was any endoleak and, if any, to determine the type of endoleak and to deal with it properly. Two cases had proximal type I endoleak, so balloon dilation was employed in one and cuff implantation in another one. Distal type I endoleak occurred in one case, but, unfortunately, the iliac artery ruptured when balloon dilation was employed, therefore the patient had to receive vascular repair

  13. Damper modules with adapted stiffness ratio

    Energy Technology Data Exchange (ETDEWEB)

    Sonnenburg, R.; Stretz, A. [ZF Sachs AG, Entwicklungszentrum, Schweinfurt (Germany)

    2011-07-15

    A mechanism for the excitation of piston rod vibrations in automotive damper modules is discussed by a simple model. An improved nonlinear model based on elasticity effects leads to good simulation results. It is shown theoretically and experimentally that the adaptation of the stiffness of the piston rod bushing to the ''stiffness'' of the damper force characteristic can eliminate the piston rod oscillations completely. (orig.)

  14. OroSTIFF: Face-referenced measurement of perioral stiffness in health and disease.

    Science.gov (United States)

    Chu, Shin-Ying; Barlow, Steven M; Kieweg, Douglas; Lee, Jaehoon

    2010-05-28

    A new device and automated measurement technology known as OroSTIFF is described to characterize non-participatory perioral stiffness in healthy adults for eventual application to patients with orofacial movement disorders associated with neuromotor disease, traumatic injury, or congenital clefts of the upper lip. Previous studies of perioral biomechanics required head stabilization for extended periods of time during measurement, which precluded sampling patients with involuntary body/head movements (dyskinesias), or pediatric subjects. The OroSTIFF device is face-referenced and avoids the complications associated with head-restraint. Supporting data of non-participatory perioral tissue stiffness using OroSTIFF are included from 10 male and 10 female healthy subjects. The OroSTIFF device incorporates a pneumatic glass air cylinder actuator instrumented for pressure, and an integrated subminiature displacement sensor to encode lip aperture. Perioral electromyograms were simultaneously sampled to confirm passive muscle state for the superior and inferior divisions of the orbicularis oris muscles. Perioral stiffness, derived as a quotient from resultant force (DeltaF) and interangle span (DeltaX), was modeled with multilevel regression techniques. Real-time calculation of the perioral stiffness function demonstrated a significant quadratic relation between imposed interangle stretch and resultant force. This stiffness growth function also differed significantly between males and females. This study demonstrates the OroSTIFF 'proof-of-concept' for cost-effective non-invasive stimulus generation and derivation of perioral stiffness in a group of healthy unrestrained adults, and a case study to illustrate the dose-dependent effects of Levodopa on perioral stiffness in an individual with advanced Parkinson's disease who exhibited marked dyskinesia and rigidity. Copyright 2010 Elsevier Ltd. All rights reserved.

  15. Arterial Stiffness and Walk Time in Patients with End-Stage Renal Disease

    Directory of Open Access Journals (Sweden)

    Abbi D. Lane

    2013-04-01

    Full Text Available Background: End-stage renal disease patients experience increased prevalence of cardiovascular disease. Heart-artery interaction may be shifted, impacting blood pressure lability, and exercise tolerance. The coupling ratio consists of the ratio of indexed arterial elastance (EaI, arterial load to ElvI, a measure of cardiac contractility or stiffness. Our purpose was to explore the relationship between elastances and functional capacity. We hypothesized that arterial stiffness (central pulse wave velocity, PWV and elastances would be correlated to shuttle walk time. Methods: We used applanation tonometry, ultrasonography, and a shuttle walk test to evaluate our hypothesis. Spearman's correlations were used to assess relationships between variables. Block regression was also performed. Results: Forty-two subjects on maintenance hemodialysis participated. Average age=44±5 years, body surface area=2.01 kg/m2. Mean EaI=4.45 and mean ElvI=6.89; the coupling ratio=0.82. Mean aortic pulse pressure=51 mmHg and PWV=9.6 m/s. PWV(r=-0.385 and EaI (r=-0.424 were significantly and inversely related to walking time while stroke volume index (SVI was positively correlated to shuttle walk time (r=0.337, pConclusions: We conclude that, like other clinical populations, both arterial and heart function predict walking ability and represent potential targets for intervention; arterial stiffness and SVI are strongly related to shuttle walk time in patients with ESRD.

  16. Transcatheter valve-in-valve implantation due to severe aortic regurgitation in a degenerated aortic homograft

    DEFF Research Database (Denmark)

    Olsen, Lene Kjaer; Engstrøm, Thomas; Søndergaard, Lars

    2009-01-01

    Transcatheter aortic valve implantation (TAVI) in severe aortic stenosis has proven to be a feasible and effective treatment modality for inoperable patients. Until now, neither aortic regurgitation nor degenerated bioprostheses has been an indication for TAVI. However, this article reports...... a successful valve-in-valve implantation of a CoreValve aortic valve prosthesis through the right subclavian artery in a case of severe aortic regurgitation within a degenerated aortic homograft. The case exemplifies the possibilities of expanding the indications for TAVI, as well as other vascular access...

  17. Hemoglobin A1c levels and aortic arterial stiffness: the Cardiometabolic Risk in Chinese (CRC) study.

    Science.gov (United States)

    Liang, Jun; Zhou, Na; Teng, Fei; Zou, Caiyan; Xue, Ying; Yang, Manqing; Song, Huaidong; Qi, Lu

    2012-01-01

    The American Diabetes Association (ADA) recently published new clinical guidelines in which hemoglobin A1c (HbA1c) was recommended as a diagnostic test for diabetes. The present study was to investigate the association between HbA1c and cardiovascular risk, and compare the associations with fasting glucose and 2-hour oral glucose tolerance test (2 h OGTT). The study samples are from a community-based health examination survey in central China. Carotid-to-femoral pulse wave velocity (cfPWV) and HbA1c were measured in 5,098 men and women. After adjustment for age, sex, and BMI, the levels of HbA1c were significantly associated with an increasing trend of cfPWV in a dose-dependent fashion (P for trend trend = 0.004) and had higher blood pressure (≥120 [systolic blood pressure]/80 mmHg [diastolic blood pressure]; P for trend = 0.028) than those who were younger and had lower blood pressure (P for trend >0.05). HbA1c was related to high cfPWV, independent of conventional cardiovascular risk factors. Senior age and high blood pressure might amplify the adverse effects of HbA1c on cardiovascular risk.

  18. Hemoglobin A1c levels and aortic arterial stiffness: the Cardiometabolic Risk in Chinese (CRC study.

    Directory of Open Access Journals (Sweden)

    Jun Liang

    Full Text Available OBJECTIVE: The American Diabetes Association (ADA recently published new clinical guidelines in which hemoglobin A1c (HbA1c was recommended as a diagnostic test for diabetes. The present study was to investigate the association between HbA1c and cardiovascular risk, and compare the associations with fasting glucose and 2-hour oral glucose tolerance test (2 h OGTT. RESEARCH DESIGN AND METHODS: The study samples are from a community-based health examination survey in central China. Carotid-to-femoral pulse wave velocity (cfPWV and HbA1c were measured in 5,098 men and women. RESULTS: After adjustment for age, sex, and BMI, the levels of HbA1c were significantly associated with an increasing trend of cfPWV in a dose-dependent fashion (P for trend 0.05. CONCLUSIONS: HbA1c was related to high cfPWV, independent of conventional cardiovascular risk factors. Senior age and high blood pressure might amplify the adverse effects of HbA1c on cardiovascular risk.

  19. Higher usual dietary intake of phytoestrogens is associated with lower aortic stiffness in postmenopausal women

    NARCIS (Netherlands)

    Schouw, van der Y.T.; Pijpe, A.; Lebrun, C.E.I.; Bots, M.L.; Peeters, P.H.M.; Staveren, van W.A.; Lamberts, S.W.J.; Grobbee, D.E.

    2002-01-01

    Objective¿ Phytoestrogens have been postulated to protect against cardiovascular diseases, but few studies have focused on the effect of Western dietary phytoestrogen intake. Methods and Results¿ Four hundred three women with natural menopause either between 1987 and 1989 or between 1969 and 1979

  20. SRC-1 regulates blood pressure and aortic stiffness in female mice

    Science.gov (United States)

    Framingham Heart Study suggests that dysfunction of steroid receptor coactivator-1 may be involved in the development of hypertension. However, there is no functional evidence linking steroid receptor coactivator-1 to the regulation of blood pressure. We used immunohistochemistry to map the expressi...

  1. Stiffness of Railway Soil-Steel Structures

    Directory of Open Access Journals (Sweden)

    Machelski Czesław

    2015-12-01

    Full Text Available The considerable influence of the soil backfill properties and that of the method of compacting it on the stiffness of soil-steel structures is characteristic of the latter. The above factors (exhibiting randomness become apparent in shell deformation measurements conducted during construction and proof test loading. A definition of soil-shell structure stiffness, calculated on the basis of shell deflection under the service load, is proposed in the paper. It is demonstrated that the stiffness is the inverse of the deflection influence function used in structural mechanics. The moving load methodology is shown to be useful for testing, since it makes it possible to map the shell deflection influence line also in the case of group loads (concentrated forces, as in bridges. The analyzed cases show that the shell’s span, geometry (static scheme and the height of earth fill influence the stiffness of the structure. The soil-steel structure’s characteristic parameter in the form of stiffness k is more suitable for assessing the quality of construction works than the proposed in code geometric index ω applied to beam structures. As shown in the given examples, parameter k is more effective than stiffness parameter λ used to estimate the deformation of soil-steel structures under construction. Although the examples concern railway structures, the methodology proposed in the paper is suitable also for road bridges.

  2. Stiffness of Railway Soil-Steel Structures

    Science.gov (United States)

    Machelski, Czesław

    2015-12-01

    The considerable influence of the soil backfill properties and that of the method of compacting it on the stiffness of soil-steel structures is characteristic of the latter. The above factors (exhibiting randomness) become apparent in shell deformation measurements conducted during construction and proof test loading. A definition of soil-shell structure stiffness, calculated on the basis of shell deflection under the service load, is proposed in the paper. It is demonstrated that the stiffness is the inverse of the deflection influence function used in structural mechanics. The moving load methodology is shown to be useful for testing, since it makes it possible to map the shell deflection influence line also in the case of group loads (concentrated forces), as in bridges. The analyzed cases show that the shell's span, geometry (static scheme) and the height of earth fill influence the stiffness of the structure. The soil-steel structure's characteristic parameter in the form of stiffness k is more suitable for assessing the quality of construction works than the proposed in code geometric index ω applied to beam structures. As shown in the given examples, parameter k is more effective than stiffness parameter λ used to estimate the deformation of soil-steel structures under construction. Although the examples concern railway structures, the methodology proposed in the paper is suitable also for road bridges.

  3. Statins for aortic valve stenosis

    Directory of Open Access Journals (Sweden)

    Luciana Thiago

    Full Text Available ABSTRACT BACKGROUND: Aortic valve stenosis is the most common type of valvular heart disease in the USA and Europe. Aortic valve stenosis is considered similar to atherosclerotic disease. Some studies have evaluated statins for aortic valve stenosis. OBJECTIVES: To evaluate the effectiveness and safety of statins in aortic valve stenosis. METHODS: Search methods: We searched the Cochrane Central Register of Controlled Trials (CENTRAL, MEDLINE, Embase, LILACS - IBECS, Web of Science and CINAHL Plus. These databases were searched from their inception to 24 November 2015. We also searched trials in registers for ongoing trials. We used no language restrictions. Selection criteria: Randomized controlled clinical trials (RCTs comparing statins alone or in association with other systemic drugs to reduce cholesterol levels versus placebo or usual care. Data collection and analysis: Primary outcomes were severity of aortic valve stenosis (evaluated by echocardiographic criteria: mean pressure gradient, valve area and aortic jet velocity, freedom from valve replacement and death from cardiovascular cause. Secondary outcomes were hospitalization for any reason, overall mortality, adverse events and patient quality of life. Two review authors independently selected trials for inclusion, extracted data and assessed the risk of bias. The GRADE methodology was employed to assess the quality of result findings and the GRADE profiler (GRADEPRO was used to import data from Review Manager 5.3 to create a 'Summary of findings' table. MAIN RESULTS: We included four RCTs with 2360 participants comparing statins (1185 participants with placebo (1175 participants. We found low-quality evidence for our primary outcome of severity of aortic valve stenosis, evaluated by mean pressure gradient (mean difference (MD -0.54, 95% confidence interval (CI -1.88 to 0.80; participants = 1935; studies = 2, valve area (MD -0.07, 95% CI -0.28 to 0.14; participants = 127; studies = 2

  4. Statins for aortic valve stenosis.

    Science.gov (United States)

    Thiago, Luciana; Tsuji, Selma Rumiko; Nyong, Jonathan; Puga, Maria Eduarda Dos Santos; Góis, Aécio Flávio Teixeira de; Macedo, Cristiane Rufino; Valente, Orsine; Atallah, Álvaro Nagib

    2016-01-01

    Aortic valve stenosis is the most common type of valvular heart disease in the USA and Europe. Aortic valve stenosis is considered similar to atherosclerotic disease. Some studies have evaluated statins for aortic valve stenosis. To evaluate the effectiveness and safety of statins in aortic valve stenosis. Search methods: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, LILACS - IBECS, Web of Science and CINAHL Plus. These databases were searched from their inception to 24 November 2015. We also searched trials in registers for ongoing trials. We used no language restrictions.Selection criteria: Randomized controlled clinical trials (RCTs) comparing statins alone or in association with other systemic drugs to reduce cholesterol levels versus placebo or usual care. Data collection and analysis: Primary outcomes were severity of aortic valve stenosis (evaluated by echocardiographic criteria: mean pressure gradient, valve area and aortic jet velocity), freedom from valve replacement and death from cardiovascular cause. Secondary outcomes were hospitalization for any reason, overall mortality, adverse events and patient quality of life.Two review authors independently selected trials for inclusion, extracted data and assessed the risk of bias. The GRADE methodology was employed to assess the quality of result findings and the GRADE profiler (GRADEPRO) was used to import data from Review Manager 5.3 to create a 'Summary of findings' table. We included four RCTs with 2360 participants comparing statins (1185 participants) with placebo (1175 participants). We found low-quality evidence for our primary outcome of severity of aortic valve stenosis, evaluated by mean pressure gradient (mean difference (MD) -0.54, 95% confidence interval (CI) -1.88 to 0.80; participants = 1935; studies = 2), valve area (MD -0.07, 95% CI -0.28 to 0.14; participants = 127; studies = 2), and aortic jet velocity (MD -0.06, 95% CI -0.26 to 0

  5. Casein improves brachial and central aortic diastolic blood pressure in overweight adolescents: a randomised, controlled trial

    DEFF Research Database (Denmark)

    Arnberg, Karina; Larnkjær, Anni; Michaelsen, Kim F.

    2013-01-01

    of water, skimmed milk, whey or casein for 12 weeks. The milk-based test drinks contained 35 g protein/l. The effects were compared with the water group and a pretest control group consisting of thirty-two of the adolescents followed 12 weeks before the start of the intervention. Outcomes were brachial...... and central aortic BP, pulse wave velocity and augmentation index, serum C-reactive protein and blood lipids. Brachial and central aortic diastolic BP (DBP) decreased by 2·7% (P= 0·036) and 2·6% (P = 0·048), respectively, within the casein group and the changes were significantly different from those...... stiffness or blood lipid concentrations. A high intake of casein improves DBP in overweight adolescents. Thus, casein may be beneficial for younger overweight subjects in terms of reducing the longterm risk of CVD. In contrast, whey protein seems to increase BP compared with drinking water; however, water...

  6. The associations of cardiorespiratory fitness, adiposity and sports participation with arterial stiffness in youth with chronic diseases or physical disabilities.

    Science.gov (United States)

    Haapala, Eero A; Lankhorst, Kristel; de Groot, Janke; Zwinkels, Maremka; Verschuren, Olaf; Wittink, Harriet; Backx, Frank Jg; Visser-Meily, Anne; Takken, Tim

    2017-07-01

    Background The evidence on the associations of cardiorespiratory fitness, body adiposity and sports participation with arterial stiffness in children and adolescents with chronic diseases or physical disabilities is limited. Methods Altogether 140 children and adolescents with chronic diseases or physical disabilities participated in this cross-sectional study. Cardiorespiratory fitness was assessed using maximal exercise test with respiratory gas analyses either using shuttle run, shuttle ride, or cycle ergometer test. Cardiorespiratory fitness was defined as peak oxygen uptake by body weight or fat-free mass. Body adiposity was assessed using waist circumference, body mass index standard deviation score and body fat percentage. Sports participation was assessed by a questionnaire. Aortic pulse wave velocity and augmentation index were assessed by a non-invasive oscillometric tonometry device. Results Peak oxygen uptake/body weight (standardised regression coefficient β -0.222, 95% confidence interval (CI) -0.386 to -0.059, P = 0.002) and peak oxygen uptake/fat-free mass (β -0.173, 95% CI -0.329 to -0.017, P = 0.030) were inversely and waist circumference directly (β 0.245, 95% CI 0.093 to 0.414, P = 0.002) associated with aortic pulse wave velocity. However, the associations of the measures of cardiorespiratory fitness with aortic pulse wave velocity were attenuated after further adjustment for waist circumference. A higher waist circumference (β -0.215, 95% CI -0.381 to -0.049, P = 0.012) and a higher body mass index standard deviation score (β 0.218, 95% CI -0.382 to -0.054, P = 0.010) were related to lower augmentation index. Conclusions Poor cardiorespiratory fitness and higher waist circumference were associated with increased arterial stiffness in children and adolescents with chronic diseases and physical disabilities. The association between cardiorespiratory fitness and arterial stiffness was partly explained by waist

  7. Deficient Circumferential Growth Is the Primary Determinant of Aortic Obstruction Attributable to Partial Elastin Deficiency.

    Science.gov (United States)

    Jiao, Yang; Li, Guangxin; Korneva, Arina; Caulk, Alexander W; Qin, Lingfeng; Bersi, Matthew R; Li, Qingle; Li, Wei; Mecham, Robert P; Humphrey, Jay D; Tellides, George

    2017-05-01

    Williams syndrome is characterized by obstructive aortopathy attributable to heterozygous loss of ELN , the gene encoding elastin. Lesions are thought to result primarily from excessive smooth muscle cell (SMC) proliferation and consequent medial expansion, although an initially smaller caliber and increased stiffness of the aorta may contribute to luminal narrowing. The relative contributions of such abnormalities to the obstructive phenotype had not been defined. We quantified determinants of luminal stenosis in thoracic aortas of Eln -/- mice incompletely rescued by human ELN . Moderate obstruction was largely because of deficient circumferential growth, most prominently of ascending segments, despite increased axial growth. Medial thickening was evident in these smaller diameter elastin-deficient aortas, with medial area similar to that of larger diameter control aortas. There was no difference in cross-sectional SMC number between mutant and wild-type genotypes at multiple stages of postnatal development. Decreased elastin content was associated with medial fibrosis and reduced aortic distensibility because of increased structural stiffness but preserved material stiffness. Elastin-deficient SMCs exhibited greater contractile-to-proliferative phenotypic modulation in vitro than in vivo. We confirmed increased medial collagen without evidence of increased medial area or SMC number in a small ascending aorta with thickened media of a Williams syndrome subject. Deficient circumferential growth is the predominant mechanism for moderate obstructive aortic disease resulting from partial elastin deficiency. Our findings suggest that diverse aortic manifestations in Williams syndrome result from graded elastin content, and SMC hyperplasia causing medial expansion requires additional elastin loss superimposed on ELN haploinsufficiency. © 2017 American Heart Association, Inc.

  8. Aortic intramural hematoma : assessment of clinical and radiological features in comparison to acute aortic dissection

    International Nuclear Information System (INIS)

    Yoon, Kwon Ha; Hwang, Jae Cheol; Lee, Jin Seong; Kang, Duk Hyun; Song, Jae Kwan; Song, Koun Sik; Lim, Tae Hwan

    1996-01-01

    To compare the clinical and radiological features of aortic intramural hematoma(IMH) to those of acute aortic dissection(AD). We analyzed the clinical and radiological features of 12 patients with aortic IMH and 43 patients with acute AD. In aortic IMH, the diagnoses were made by means of both CT and transesophageal echocardiography(TEE) and included two surgically proven cases. In acute AD, the diagnoses were made by means of CT and TEE and included 21 surgically proven cases. We compared patients ages, etiologies, the extent of the disease, the presence or absence of aortic branch involvement, complications, and outcomes. Aortic IMH tended to develop in older patients (67.8±7.9 vs. 50.4±13.4, P .05). In aortic IMH, there was no involvement of aortic branches, whereas in acute AD, 14(33%) patients showed involvement of one or more aortic branches. Complications of aortic IMH included pericardial effusion (n=2) and pleural effusion (n=4);in acute AD, pericardial effusion (n=7), pleural effusion (n=4), aortic insufficiency (n=8), cerebral infarction (n=3), renal infarction (n=4) and spinal infarction (n=1) were seen. There was one (8%) death due to aortic IMH and ten (23%) deaths due to acute AD (p<.01). Aortic IMH is characterized by its occurrence in older patients with hypertension, a less frequent incidence of complications, and a more favorable outcome than acute AD

  9. Decreased expression of fibulin-4 in aortic wall of aortic dissection.

    Science.gov (United States)

    Huawei, P; Qian, C; Chuan, T; Lei, L; Laing, W; Wenlong, X; Wenzhi, L

    2014-02-01

    In this research, we will examine the expression of Fibulin-4 in aortic wall to find out its role in aortic dissection development. The samples of aortic wall were obtained from 10 patients operated for acute ascending aortic dissection and five patients for chronic ascending aortic dissection. Another 15 pieces of samples from patients who had coronary artery bypass were as controls. The aortic samples were stained with aldehyde magenta dyeing to evaluate the arrangement of elastic fibers. The Fibulin-4 protein and mRNA expression were both determined by Western blot and realtime quantitative polymerase chain reaction. Compared with the control group, both in acute and chronic ascending aortic dissection, elastic fiber fragments increased and the expression of fibulin-4 protein significantly decreased (P= 0.045 < 0.05). The level of fibulin-4 mRNA decreased in acute ascending aortic dissection (P= 0.034 < 0.05), while it increased in chronic ascending aortic dissection (P=0.004 < 0.05). The increased amounts of elastic fiber fragments were negatively correlated with the expression of fibulin-4 mRNA in acute ascending aortic dissection. In conclusion, in aortic wall of ascending aortic dissection, the expression of fibulin-4 protein decreased and the expression of fibulin-4 mRNA was abnormal. Fibulin-4 may play an important role in the pathogenesis of aortic dissection.

  10. Molecular and cellular mechanisms of aortic stenosis.

    Science.gov (United States)

    Yetkin, Ertan; Waltenberger, Johannes

    2009-06-12

    Calcific aortic stenosis is the most common cause of aortic valve replacement in developed countries, and this condition increases in prevalence with advancing age. The fibrotic thickening and calcification are common eventual endpoint in both non-rheumatic calcific and rheumatic aortic stenoses. New observations in human aortic valves support the hypothesis that degenerative valvular aortic stenosis is the result of active bone formation in the aortic valve, which may be mediated through a process of osteoblast-like differentiation in these tissues. Additionally histopathologic evidence suggests that early lesions in aortic valves are not just a disease process secondary to aging, but an active cellular process that follows the classical "response to injury hypothesis" similar to the situation in atherosclerosis. Although there are similarities with the risk factor and as well as with the process of atherogenesis, not all the patients with coronary artery disease or atherosclerosis have calcific aortic stenosis. This review mainly focuses on the potential vascular and molecular mechanisms involved in the pathogenesis of aortic valve stenosis. Namely extracellular matrix remodeling, angiogenesis, inflammation, and eventually osteoblast-like differentiation resulting in bone formation have been shown to play a role in the pathogenesis of calcific aortic stenosis. Several mediators related to underlying mechanisms, including growth factors especially transforming growth factor-beta1 and vascular endothelial growth factors, angiogenesis, cathepsin enzymes, adhesion molecules, bone regulatory proteins and matrix metalloproteinases have been demonstrated, however the target to be attacked is not defined yet.

  11. Perforation of the right aortic valve cusp: complication of ventricular septal defect closure with a modified Rashkind umbrella.

    Science.gov (United States)

    Vogel, M; Rigby, M L; Shore, D

    1996-01-01

    An 18-month-old boy with a perimembranous ventricular septal defect (VSD) had undergone transcatheter closure of the defect with a modified 17 mm Rashkind umbrella device at age 4 months (weight 3.8 kg). The clinical signs of a VSD persisted, and he developed aortic incompetence, first detected 5 months after the procedure, which progressed from mild to moderate. A three-dimensional echocardiographic study demonstrated that one of the four arms holding the umbrella was protruding into the aortic valve and had perforated the right aortic valve cusp. This diagnosis was confirmed at subsequent surgery. Surgical repair of the perforated right aortic valve leaflet was necessary. The umbrella was adherent to the tricuspid valve and could not be removed. Instead it was left in situ, but three of the stainless steel arms were cut off. When umbrella closure of a perimembranous VSD is undertaken, the close proximity of part of the distal umbrella to the aortic valve can lead to aortic regurgitation.

  12. Blood pressure and arterial stiffness in obese children and adolescents.

    Science.gov (United States)

    Hvidt, Kristian Nebelin

    2015-03-01

    Obesity, elevated blood pressure (BP) and arterial stiffness are risk factors for cardiovascular disease. A strong relationship exists between obesity and elevated BP in both children and adults. Obesity and elevated BP in childhood track into adult life increasing the risk of cardiovascular disease in adulthood. Ambulatory BP is the most precise measure to evaluate the BP burden, whereas carotid-femoral pulse wave velocity (cfPWV) is regarded as the gold standard for evaluating arterial (i.e. aortic) stiffness. These measures might contribute to a better understanding of obesity's adverse impact on the cardiovascular system, and ultimately a better prevention and treatment of childhood obesity. The overall aim of the present PhD thesis is to investigate arterial stiffness and 24-hour BP in obese children and adolescents, and evaluate whether these measures are influenced by weight reduction. The present PhD thesis is based on four scientific papers.  In a cross-sectional design, 104 severe obese children and adolescents with an age of 10-18 years were recruited when newly referred to the Children's Obesity Clinic, Holbæk University Hospital, and compared to 50 normal weighted age and gender matched control individuals. Ambulatory BP was measured, and cfPWV was investigated in two ways in respect to the distance measure of aorta; the previously recommended length - the so called subtracted distance, and the currently recommended length - the direct distance. In a longitudinal design, the obese patients were re-investigated after one-year of lifestyle intervention at the Children's Obesity Clinic in purpose of reducing the degree of obesity. In the cross-sectional design, the obese group had higher measures of obesity, while matched for age, gender and height, when compared to the control group. In the longitudinal design, 74% of the 72 followed up obese patients experienced a significant weight reduction. CfPWV was dependent on the method used to measure the

  13. Aorto-aortic intrathoracic bypass in surgical treatment of aortic

    International Nuclear Information System (INIS)

    Gutierrez Perez, F.; Duran Reyes, A.; Bigalli, D.; Filgueira Berobide, J.

    1998-01-01

    The prevalence of coarctation of the aorta is 6.5 percent of all congenital heart defects, according to national and international data. There is a restenosis rate of patients after surgery. Factors that influence this evolution depends on the age at which patients underwent surgery for the first time the anatomy of the aortic arch and type of surgical technique. Several procedures can be used to correct the coarctation, which include surgery and balloon catheter dilation. We present here a case of a patient of 22 years old, with a recurrent coarctation of the aorta studied by echocardiography and magnetic resonance imaging. The patient underwent surgery a third time. We used an anterior approach (median sternotomy) and performed an aortic bypass graft, intrathoracic, under cardiopulmonary bypass. Evolved favorably and was discharged on the sixth day of post operative day (Author) [es

  14. Aortic root geometry in aortic stenosis patients (a SEAS substudy)

    DEFF Research Database (Denmark)

    Bahlmann, Edda; Nienaber, Christoph A; Cramariuc, Dana

    2011-01-01

    -specified requirements for the aortic root geometry for current available prostheses, CoreValve and Edwards-Sapien. The ratio of sinus of Valsalva height to sinus width was 1:2. In multivariate linear regression analysis, larger sinus of Valsalva height was associated with older age, larger sinus of Valsalva diameter......, lower ejection fraction and smaller supracoronary diameter (multiple R(2) = 0.19, PSapien prosthesis in 66.9%. Overall, annular dimension feasible for TAVI using any available prosthesis was found...

  15. Soluble receptor for advanced glycation end-product levels are related to albuminuria and arterial stiffness in essential hypertension.

    Science.gov (United States)

    Dimitriadis, K; Tsioufis, C; Kasiakogias, A; Miliou, A; Poulakis, M; Kintis, K; Bafakis, I; Benardis, E; Tousoulis, D; Stefanadis, C

    2013-04-01

    Emerging evidence suggests that the soluble receptor for advanced glycation end-products (sRAGE) is implicated in the development of vascular disease. We investigated the interrelationships of sRAGE with albumin to creatinine ratio (ACR) and arterial stiffness in essential hypertension. In 309 untreated non-diabetic hypertensives, ACR values were determined as the mean of three non-consecutive morning spot urine samples and aortic stiffness was evaluated on the basis of carotid to femoral pulse wave velocity (c-f PWV). In all subjects, venous blood sampling was performed for the estimation of sRAGE levels. Patients with low (n = 155) compared to those with high sRAGE values (n = 154) had greater 24-h systolic BP (140 ± 8 vs. 134 ± 7 mmHg, p involvement of sRAGE in the progression of hypertensive vascular damage. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Single motor–variable stiffness actuator using bistable switching mechanisms for independent motion and stiffness control

    NARCIS (Netherlands)

    Groothuis, Stefan; Carloni, Raffaella; Stramigioli, Stefano

    This paper presents a proof of concept of a variable stiffness actuator (VSA) that uses only one (high power) input motor. In general, VSAs use two (high power) motors to be able to control both the output position and the output stiffness, which possibly results in a heavy, and bulky system. In

  17. The cardiovascular effects of aortic clamping and unclamping

    African Journals Online (AJOL)

    aortic clamping is that afterload and blood pressure increase, and ... individually, albeit they interact with each other. The degree of ... position of the aortic clamp, the greater the increase ... the increase in preload in response to aortic clamping.

  18. Retrograde Ascending Dissection After Thoracic Endovascular Aortic Repair Combined With the Chimney Technique and Successful Open Repair Using the Frozen Elephant Trunk Technique.

    Science.gov (United States)

    Hirano, Koji; Tokui, Toshiya; Nakamura, Bun; Inoue, Ryosai; Inagaki, Masahiro; Maze, Yasumi; Kato, Noriyuki

    2018-01-01

    The chimney technique can be combined with thoracic endovascular aortic repair (TEVAR) to both obtain an appropriate landing zone and maintain blood flow of the arch vessels. However, surgical repair becomes more complicated if retrograde type A aortic dissection occurs after TEVAR with the chimney technique. We herein report a case involving a 73-year-old woman who developed a retrograde ascending dissection 3 months after TEVAR for acute type B aortic dissection. To ensure an adequate proximal sealing distance, the proximal edge of the stent graft was located at the zone 2 level and an additional bare stent was placed at the left subclavian artery (the chimney technique) at the time of TEVAR. Enhanced computed tomography revealed an aortic dissection involving the ascending aorta and aortic arch. Surgical aortic repair using the frozen elephant trunk technique was urgently performed. The patient survived without stroke, paraplegia, renal failure, or other major complications. Retrograde ascending dissection can occur after TEVAR combined with the chimney technique. The frozen elephant trunk technique is useful for surgical repair in such complicated cases.

  19. Indexing aortic valve area by body surface area increases the prevalence of severe aortic stenosis

    DEFF Research Database (Denmark)

    Jander, Nikolaus; Gohlke-Bärwolf, Christa; Bahlmann, Edda

    2014-01-01

    To account for differences in body size in patients with aortic stenosis, aortic valve area (AVA) is divided by body surface area (BSA) to calculate indexed AVA (AVAindex). Cut-off values for severe stenosis are......To account for differences in body size in patients with aortic stenosis, aortic valve area (AVA) is divided by body surface area (BSA) to calculate indexed AVA (AVAindex). Cut-off values for severe stenosis are...

  20. Impact of Discordant Views in the Management of Descending Thoracic Aortic Aneurysm.

    Science.gov (United States)

    Chiu, Peter; Sailer, Anna-Margaretha; Baiocchi, Michael; Goldstone, Andrew B; Schaffer, Justin M; Trojan, Jeff; Fleischmann, Dominik; Mitchell, R Scott; Miller, D Craig; Dake, Michael D; Woo, Y Joseph; Lee, Jason T; Fischbein, Michael P

    2017-01-01

    Thoracic endovascular aortic repair has a lower perceived risk than open surgical repair and has become an increasingly popular alternative. Whether general consensus exists regarding candidacy for either operation among open and endovascular specialists is unknown. A retrospective review of isolated descending thoracic aortic aneurysm at our institution between January 2005 and October 2015 was performed, excluding trauma and dissection. Two cardiac surgeons, 2 cardiovascular surgeons, 1 vascular surgeon, and 1 interventional radiologist gave their preference for open vs endovascular repair. Interobserver agreement was assessed with the kappa coefficient. k-means clustering agnostically grouped various patterns of agreement. The mean rating was predicted using least absolute shrinkage and selection operator regression. Negative binomial regression predicted the discrepancy between our panel of raters and the historical operation. Generalized estimating equation modeling was then used to evaluate the association between the extent of discrepancy and the adverse perioperative outcome. There were 77 patients with preoperative imaging studies. Pairwise interobserver agreement was only fair (median weighted kappa 0.270 [interquartile range 0.211-0.404]). Increasing age and proximal neck length predicted an increasing preference for thoracic endovascular aortic repair in our panel; larger proximal neck diameter predicted a general preference for open surgical repair. Increasing proximal neck diameter predicted a larger discrepancy between our panel and the historical operation. Greater discrepancy was associated with adverse outcome. Substantial disagreement existed among our panel, and an exploratory analysis of the effect of increasing discrepancy demonstrated an association with adverse perioperative outcome. An investigation of the effect of a thoracic aortic team with open and endovascular specialists is warranted. Copyright © 2017 Elsevier Inc. All rights

  1. Development of a stiffness-angle law for simplifying the measurement of human hair stiffness.

    Science.gov (United States)

    Jung, I K; Park, S C; Lee, Y R; Bin, S A; Hong, Y D; Eun, D; Lee, J H; Roh, Y S; Kim, B M

    2018-04-01

    This research examines the benefits of caffeine absorption on hair stiffness. To test hair stiffness, we have developed an evaluation method that is not only accurate, but also inexpensive. Our evaluation method for measuring hair stiffness culminated in a model, called the Stiffness-Angle Law, which describes the elastic properties of hair and can be widely applied to the development of hair care products. Small molecules (≤500 g mol -1 ) such as caffeine can be absorbed into hair. A common shampoo containing 4% caffeine was formulated and applied to hair 10 times, after which the hair stiffness was measured. The caffeine absorption of the treated hair was observed using Fourier-transform infrared spectroscopy (FTIR) with a focal plane array (FPA) detector. Our evaluation method for measuring hair stiffness consists of a regular camera and a support for single strands of hair. After attaching the hair to the support, the bending angle of the hair was observed with a camera and measured. Then, the hair strand was weighed. The stiffness of the hair was calculated based on our proposed Stiffness-Angle Law using three variables: angle, weight of hair and the distance the hair was pulled across the support. The caffeine absorption was confirmed by FTIR analysis. The concentration of amide bond in the hair certainly increased due to caffeine absorption. After caffeine was absorbed into the hair, the bending angle and weight of the hair changed. Applying these measured changes to the Stiffness-Angle Law, it was confirmed that the hair stiffness increased by 13.2% due to caffeine absorption. The theoretical results using the Stiffness-Angle Law agree with the visual examinations of hair exposed to caffeine and also the known results of hair stiffness from a previous report. Our evaluation method combined with our proposed Stiffness-Angle Law effectively provides an accurate and inexpensive evaluation technique for measuring bending stiffness of human hair. © 2018

  2. VARIABLE STIFFNESS HAND PROSTHESIS: A SYSTEMATIC REVIEW

    Directory of Open Access Journals (Sweden)

    S. Cecilia Tapia-Siles

    2017-06-01

    Full Text Available Prosthetics is an important field in engineering due to the large number of amputees worldwide and the associated problems such as limited functionality of the state of the art. An important functionality of the human hand is its capability of adjusting the stiffness of the joints depending on the currently performed task. For the development of new technology it is important to understand the limitations of existing resources. As part of our efforts to develop a variable stiffness grasper for developing countries a systematic review was performed covering technology of body powered and myoelectric hand prosthesis. Focus of the review is readiness of prosthetic hands regarding their capability of controlling the stiffness of the end effector. Publications sourced through three different digital libraries were systematically reviewed on the basis of the PRISMA standard. We present a search strategy as well as the PRISMA assessment of the resulting records which covered 321 publications. The records were assessed and the results are presented for the ability of devices to control their joint stiffness. The review indicates that body powered prosthesis are preferred to myoelectric hands due to the reduced cost, the simplicity of use and because of their inherent ability to provide feedback to the user. Stiffness control was identified but has not been fully covered in the current state of the art. In addition we summarise the identified requirements on prosthetic hands as well as related information which can support the development of new prosthetics.

  3. A Novel Variable Stiffness Mechanism Capable of an Infinite Stiffness Range and Unlimited Decoupled Output Motion

    Directory of Open Access Journals (Sweden)

    Stefan Groothuis

    2014-06-01

    Full Text Available In this paper, a novel variable stiffness mechanism is presented, which is capable of achieving an output stiffness with infinite range and an unlimited output motion, i.e., the mechanism output is completely decoupled from the rotor motion, in the zero stiffness configuration. The mechanism makes use of leaf springs, which are engaged at different positions by means of two movable supports, to realize the variable output stiffness. The Euler–Bernoulli leaf spring model is derived and validated through experimental data. By shaping the leaf springs, it is shown that the stiffness characteristic of the mechanism can be changed to fulfill different application requirements. Alternative designs can achieve the same behavior with only one leaf spring and one movable support pin.

  4. Preliminary study on leadership proximity

    Directory of Open Access Journals (Sweden)

    Ghinea Valentina Mihaela

    2017-07-01

    Full Text Available In general, it is agreed that effective leadership requires a certain degree of proximity, either physical or mental, which enables leaders to maintain control over their followers and communicate their vision. Although we agree with the leadership proximity principles which states that leaders are able to efficiently serve only those people with whom they interact frequently, in this article we focus instead on the disadvantages of being too close and the way in which close proximity can actually hurt the effectiveness of leadership. The main effects that we discuss regard the way in which proximity and familiarity allow followers to see the weaknesses and faults of the leader much more easily and thus diminish the leader’s heroic aura, and the emotional bias that results from a leader being too familiar with his followers which will impede the process of rational decision making. As a result, we argue that there exists a functional proximity which allows the leader the necessary space in which to perform effective identity work and to hide the backstage aspects of leadership, while also allowing him an emotional buffer zone which will enable him to maintain the ability to see clearly and make rational decisions.

  5. Aortic valvuloplasty of calcific aortic stenosis with monofoil and trefoil balloon catheters: practical considerations

    NARCIS (Netherlands)

    S. Plante (Sylvain); M.J.B.M. van den Brand (Marcel); L.C.P. van Veen; C. di Mario (Carlo); C.E. Essed; K.J. Beatt (Kevin); P.W.J.C. Serruys (Patrick)

    1990-01-01

    textabstractIn order to evaluate the relation between balloon design (monofoil, trefoil) and valvular configuration, experimental aortic valvuloplasty was performed in four post-mortem hearts with calcific aortic stenosis of various morphology. The degree of obstruction of the aortic orifice was

  6. Association Between Gout and Aortic Stenosis.

    Science.gov (United States)

    Chang, Kevin; Yokose, Chio; Tenner, Craig; Oh, Cheongeun; Donnino, Robert; Choy-Shan, Alana; Pike, Virginia C; Shah, Binita D; Lorin, Jeffrey D; Krasnokutsky, Svetlana; Sedlis, Steven P; Pillinger, Michael H

    2017-02-01

    An independent association between gout and coronary artery disease is well established. The relationship between gout and valvular heart disease, however, is unclear. The aim of this study was to assess the association between gout and aortic stenosis. We performed a retrospective case-control study. Aortic stenosis cases were identified through a review of outpatient transthoracic echocardiography (TTE) reports. Age-matched controls were randomly selected from patients who had undergone TTE and did not have aortic stenosis. Charts were reviewed to identify diagnoses of gout and the earliest dates of gout and aortic stenosis diagnosis. Among 1085 patients who underwent TTE, 112 aortic stenosis cases were identified. Cases and nonaortic stenosis controls (n = 224) were similar in age and cardiovascular comorbidities. A history of gout was present in 21.4% (n = 24) of aortic stenosis subjects compared with 12.5% (n = 28) of controls (unadjusted odds ratio 1.90, 95% confidence interval 1.05-3.48, P = .038). Multivariate analysis retained significance only for gout (adjusted odds ratio 2.08, 95% confidence interval 1.00-4.32, P = .049). Among subjects with aortic stenosis and gout, gout diagnosis preceded aortic stenosis diagnosis by 5.8 ± 1.6 years. The age at onset of aortic stenosis was similar among patients with and without gout (78.7 ± 1.8 vs 75.8 ± 1.0 years old, P = .16). Aortic stenosis patients had a markedly higher prevalence of precedent gout than age-matched controls. Whether gout is a marker of, or a risk factor for, the development of aortic stenosis remains uncertain. Studies investigating the potential role of gout in the pathophysiology of aortic stenosis are warranted and could have therapeutic implications. Published by Elsevier Inc.

  7. Aortic and Cardiac Structure and Function Using High-Resolution Echocardiography and Optical Coherence Tomography in a Mouse Model of Marfan Syndrome.

    Directory of Open Access Journals (Sweden)

    Ling Lee

    Full Text Available Marfan syndrome (MFS is an autosomal-dominant disorder of connective tissue caused by mutations in the fibrillin-1 (FBN1 gene. Mortality is often due to aortic dissection and rupture. We investigated the structural and functional properties of the heart and aorta in a [Fbn1C1039G/+] MFS mouse using high-resolution ultrasound (echo and optical coherence tomography (OCT. Echo was performed on 6- and 12-month old wild type (WT and MFS mice (n = 8. In vivo pulse wave velocity (PWV, aortic root diameter, ejection fraction, stroke volume, left ventricular (LV wall thickness, LV mass and mitral valve early and atrial velocities (E/A ratio were measured by high resolution echocardiography. OCT was performed on 12-month old WT and MFS fixed mouse hearts to measure ventricular volume and mass. The PWV was significantly increased in 6-mo MFS vs. WT (366.6 ± 19.9 vs. 205.2 ± 18.1 cm/s; p = 0.003 and 12-mo MFS vs. WT (459.5 ± 42.3 vs. 205.3 ± 30.3 cm/s; p< 0.0001. PWV increased with age in MFS mice only. We also found a significantly enlarged aortic root and decreased E/A ratio in MFS mice compared with WT for both age groups. The [Fbn1C1039G/+] mouse model of MFS replicates many of the anomalies of Marfan patients including significant aortic dilation, central aortic stiffness, LV systolic and diastolic dysfunction. This is the first demonstration of the direct measurement in vivo of pulse wave velocity non-invasively in the aortic arch of MFS mice, a robust measure of aortic stiffness and a critical clinical parameter for the assessment of pathology in the Marfan syndrome.

  8. Arterial wall stiffness in patients with essential hypertension at young age

    Directory of Open Access Journals (Sweden)

    Kolesnik E.L.

    2014-11-01

    Full Text Available Research objective was investigating arterial wall stiffness in patients with hypertension at young age and assessing the relationship between subclinical target organs damage and ambulatory blood pressure monitoring (ABPM parameters. 30 male patients aged 18-35 years with essential hypertension stage I and II, hypertension 1 and 2nd grade were surveyed. The examination included general clinical methods, echocardiography, ABPM and suprasystolic sfigmography. It was found that the pulse wave velocity (PWVao (r = 0,557 p <0,01, central aortic blood pressure (SBPao (r = 0,492 p <0,01 and augmentation index (AIxao (r = 0,489 p <0.01 significantly increased with the pa¬tients’ age. Abdominal obesity (r = 0,566 p <0,01 and BMI (r = 0,599 p <0,01 impacted on the PWVao acceleration. Increasing of the left ventricular mass index (LVMI is highly associated with SBPao (r = 0,506 p <0,05 and PWVao (r = 0,434 p <0,05. According to ABPM the most significant correlation with arterial wall stiffness parameters demon¬strated diastolic blood pressure (DBP daytime level (AIxao (r = 0,418 p <0,01, with PWVao (r = 0,699 p <0.01 and SBPao (r = 0,695 p <0,01. Thus, age, excessive body weight and obesity should be considered as unfavorable factors that worsen arterial wall stiffness in patients with hypertension at the age before 35 years. Increase of DBP levels especially during the day causes maximum negative impact on the arterial wall stiffness parameters according to ABPM. Increased SBPao and PWVao in patients with hypertension at a young age are associated with increased left ventricular mass index.

  9. Acute effects of repeated bouts of aerobic exercise on arterial stiffness after glucose ingestion.

    Science.gov (United States)

    Kobayashi, Ryota; Hashimoto, Yuto; Hatakeyama, Hiroyuki; Okamoto, Takanobu

    2018-03-22

    The aim of this study was to investigate the acute repeated bouts of aerobic exercise decrease leg arterial stiffness. However, the influence of repeated bouts of aerobic exercise on arterial stiffness after glucose ingestion is unknown. The present study investigates the acute effects of repeated bouts of aerobic exercise on arterial stiffness after the 75-g oral glucose tolerance test (OGTT). Ten healthy young men (age, 23.2 ± 0.9 years) performed repeated bouts of aerobic exercise trial (RE, 65% peak oxygen uptake; two 15 min bouts of cycling performed 20 min apart) and control trial (CON, seated and resting in a quiet room) at 80 min before the 75-g OGTT on separate days in a randomized, controlled crossover fashion. Carotid-femoral (aortic) and femoral-ankle (leg) pulse wave velocity, carotid augmentation index, brachial and ankle blood pressure, heart rate and blood glucose and insulin levels were measured before (baseline) and 30, 60 and 120 min after the 75-g OGTT. Leg pulse wave velocity, ankle systolic blood pressure and blood glucose levels increased from baseline after the 75-g OGTT in the CON trial, but not in the RE trial. The present findings indicate that acute repeated bouts of aerobic exercise before glucose ingestion suppress increases in leg arterial stiffness following glucose ingestion. RE trial repeated bouts of aerobic exercise trial; CON trial control trial; BG blood glucose; VO 2peak peak oxygen uptake; PWV Pulse wave velocity; AIx carotid augmentation index; BP blood pressure; HR heart rate; CVs coefficients of variation; RPE Ratings of perceived exertion; SE standard error.

  10. Arterial Stiffness and its Correlation with the Extent of Coronary Artery Disease

    Directory of Open Access Journals (Sweden)

    Hourak Poorzand

    2018-06-01

    Full Text Available Introduction: Coronary artery disease secondary to atherosclerosis is the most common cause of mortality. Coronary angiography is the most precise method for determining the extent of disease in the coronary vascular bed. Arterial stiffness has been proposed as a marker of atherosclerosis in some studies. One of the noninvasive methods for the determination of arterial stiffness is Doppler echocardiography. In this study, we aimed to find the correlation between arterial stiffness as measured by echocardiography and the extent of coronary artery disease as evaluated through angiography. Materials and Methods: Aortic pulse wave velocity (APWV was measured by using the Doppler method in 70 patients, who were candidates for coronary angiography. The extent of coronary artery disease was determined quantitatively in terms of Friesinger index and semi-quantitatively as the number of vessels with stenosis of over 50%. Then, the correlation between arterial stiffness and these factors was evaluated. Results: The mean APWV was 9.1±5 m/s. There was a direct relationship between APWV and Friesinger index, which was not statistically significant (P=0.67. The mean APWV for patients with one-vessel disease was 4.4±1.8 m/s, while it was 9.9±3.6 m/s in patients with two and 7.9±4 m/s in three-vessel disease which did not show statistically significant difference. Conclusion: Doppler echocardiography to measure APWV was not considered as a promising tool to predict the extent of coronary artery disease.

  11. Low-gradient aortic stenosis.

    Science.gov (United States)

    Clavel, Marie-Annick; Magne, Julien; Pibarot, Philippe

    2016-09-07

    An important proportion of patients with aortic stenosis (AS) have a 'low-gradient' AS, i.e. a small aortic valve area (AVA gradient (gradient discrepancy raises uncertainty about the actual stenosis severity and thus about the indication for aortic valve replacement (AVR) if the patient has symptoms and/or left ventricular (LV) systolic dysfunction. The most frequent cause of low-gradient (LG) AS is the presence of a low LV outflow state, which may occur with reduced left ventricular ejection fraction (LVEF), i.e. classical low-flow, low-gradient (LF-LG), or preserved LVEF, i.e. paradoxical LF-LG. Furthermore, a substantial proportion of patients with AS may have a normal-flow, low-gradient (NF-LG) AS: i.e. a small AVA-low-gradient combination but with a normal flow. One of the most important clinical challenges in these three categories of patients with LG AS (classical LF-LG, paradoxical LF-LG, and NF-LG) is to differentiate a true-severe AS that generally benefits from AVR vs. a pseudo-severe AS that should be managed conservatively. A low-dose dobutamine stress echocardiography may be used for this purpose in patients with classical LF-LG AS, whereas aortic valve calcium scoring by multi-detector computed tomography is the preferred modality in those with paradoxical LF-LG or NF-LG AS. Although patients with LF-LG severe AS have worse outcomes than those with high-gradient AS following AVR, they nonetheless display an important survival benefit with this intervention. Some studies suggest that transcatheter AVR may be superior to surgical AVR in patients with LF-LG AS. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

  12. Thoracic aortic aneurysms and dissections: endovascular treatment.

    Science.gov (United States)

    Baril, Donald T; Cho, Jae S; Chaer, Rabih A; Makaroun, Michel S

    2010-01-01

    The treatment of thoracic aortic disease has changed radically with the advances made in endovascular therapy since the concept of thoracic endovascular aortic repair was first described 15 years ago. Currently, there is a diverse array of endografts that are commercially available to treat the thoracic aorta. Multiple studies, including industry-sponsored and single-institution reports, have demonstrated excellent outcomes of thoracic endovascular aortic repair for the treatment of thoracic aortic aneurysms, with less reported perioperative morbidity and mortality in comparison with conventional open repair. Additionally, similar outcomes have been demonstrated for the treatment of type B dissections. However, the technology remains relatively novel, and larger studies with longer term outcomes are necessary to more fully evaluate the role of endovascular therapy for the treatment of thoracic aortic disease. This review examines the currently available thoracic endografts, preoperative planning for thoracic endovascular aortic repair, and outcomes of thoracic endovascular aortic repair for the treatment of both thoracic aortic aneurysms and type B aortic dissections. Mt Sinai J Med 77:256-269, 2010. (c) 2010 Mount Sinai School of Medicine.

  13. Hybrid treatment of penetrating aortic ulcer

    International Nuclear Information System (INIS)

    Lara, Juan Antonio Herrero; Martins-Romeo, Daniela de Araujo; Escudero, Carlos Caparros; Falcon, Maria del Carmen Prieto; Batista, Vinicius Bianchi; Vazquez, Rosa Maria Lepe

    2015-01-01

    Penetrating atherosclerotic aortic ulcer is a rare entity with poor prognosis in the setting of acute aortic syndrome. In the literature, cases like the present one, located in the aortic arch, starting with chest pain and evolving with dysphonia, are even rarer. The present report emphasizes the role played by computed tomography in the diagnosis of penetrating atherosclerotic ulcer as well as in the differentiation of this condition from other acute aortic syndromes. Additionally, the authors describe a new therapeutic approach represented by a hybrid endovascular surgical procedure for treatment of the disease. (author)

  14. Hybrid treatment of penetrating aortic ulcer

    Energy Technology Data Exchange (ETDEWEB)

    Lara, Juan Antonio Herrero; Martins-Romeo, Daniela de Araujo; Escudero, Carlos Caparros; Falcon, Maria del Carmen Prieto; Batista, Vinicius Bianchi, E-mail: jaherrero5@hotmail.com [Unidade de Gestao Clinica (UGC) de Diagnostico por Imagem - Hosppital Universitario Virgen Macarena, Sevilha (Spain); Vazquez, Rosa Maria Lepe [Unit of Radiodiagnosis - Hospital Nuestra Senora de la Merced, Osuna, Sevilha (Spain)

    2015-05-15

    Penetrating atherosclerotic aortic ulcer is a rare entity with poor prognosis in the setting of acute aortic syndrome. In the literature, cases like the present one, located in the aortic arch, starting with chest pain and evolving with dysphonia, are even rarer. The present report emphasizes the role played by computed tomography in the diagnosis of penetrating atherosclerotic ulcer as well as in the differentiation of this condition from other acute aortic syndromes. Additionally, the authors describe a new therapeutic approach represented by a hybrid endovascular surgical procedure for treatment of the disease. (author)

  15. Plant fibre composites - porosity and stiffness

    DEFF Research Database (Denmark)

    Madsen, Bo; Thygesen, Anders; Lilholt, Hans

    2009-01-01

    Plant fibre composites contain typically a relatively large amount of porosity which influences their performance. A model, based on a modified rule of mixtures, is presented to include the influence of porosity on the composite stiffness. The model integrates the volumetric composition...... of the composites with their mechanical properties. The fibre weight fraction is used as an independent parameter to calculate the complete volumetric composition. A maximum obtainable stiffness of the composites is calculated at a certain transition fibre weight fraction, which is characterised by a best possible...... combination of high fibre volume fraction and low porosity. The model is validated with experimental data from the literature on several types of composites. A stiffness diagram is presented to demonstrate that the calculations can be used for tailoring and design of composites with a given profile...

  16. Surgery for acute Type I aortic dissection without resection of supra-aortic entry sites leads to unfavourable aortic remodelling.

    Science.gov (United States)

    Heo, Woon; Song, Suk-Won; Lee, Kwang-Hun; Lee, Shin-Young; Kim, Tae-Hoon; Baek, Min-Young; Yoo, Kyung-Jong

    2018-01-29

    This study aimed to evaluate the impact of remnant re-entries in arch branches on postoperative change in the aortic arch and descending aortic diameters and the rate of major adverse aortic events. Between January 2010 and December 2016, 249 patients underwent surgery for acute Type I aortic dissection. Patients who underwent total arch replacement, had Marfan syndrome or had intramural haematoma were excluded. Seventy-two patients with predischarge and follow-up computed tomography scans were enrolled. Patients with and without re-entries in the arch branches after surgery were assigned to the supra-aortic entry (SAE, n = 21) and no supra-aortic entry (n = 51) groups, respectively. Diameters were measured at 7 levels: the innominate artery, left common carotid artery, left subclavian artery, 20 mm distal to the left subclavian artery, pulmonary artery bifurcation, coeliac axis and maximal diameter of the descending thoracic aorta. Growth rates at the levels of the pulmonary artery bifurcation and 20 mm distal to the left subclavian artery were significantly higher in the SAE group than in the no supra-aortic entry group. The rate of freedom from major adverse aortic events (annual growth >5 mm or maximal diameter of the descending thoracic aorta >50 mm) at 5 years was significantly higher in the no supra-aortic entry group than in the SAE group. Remnant SAE leads to unfavourable aortic remodelling after acute Type I aortic dissection repair. © The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  17. Prosthesis-patient mismatch after transcatheter aortic valve implantation with the Medtronic-Corevalve bioprosthesis.

    Science.gov (United States)

    Jilaihawi, Hasan; Chin, Derek; Spyt, Tomasz; Jeilan, Mohamed; Vasa-Nicotera, Mariuca; Bence, Johan; Logtens, Elaine; Kovac, Jan

    2010-04-01

    Prosthesis-patient mismatch (P-PM) is an important determinant of morbidity and mortality following open aortic valve replacement. The aims of this study were to report its incidence and determinants following transcatheter aortic valve implantation (TAVI) with the Corevalve bioprosthesis, which have-thus far-not been described. Patients with severe calcific aortic stenosis received TAVI with the Corevalve bioprosthesis via transfemoral route. Following TAVI, moderate P-PM was defined as indexed aortic valve effective orifice area (AVAi) Clinical, echocardiographic, and procedural factors relating to P-PM were studied. Optimal device position was defined on fluoroscopy as final position of the proximal aspect of the Corevalve stent frame 5-10 mm below the native aortic annulus. Between January 2007 and January 2009, 50 consecutive patients underwent TAVI in a single centre with the Corevalve bioprosthesis. Mean age was 82.8 years (SD 5.9; 70-93) and 48% were male. P-PM occurred in 16 of 50 cases (32%). Optimal position was achieved in 50% of cases. P-PM was unrelated to age, annulus size, LVOT size, Corevalve size, aortic angulation, ejection fraction, and sex. It was inversely correlated to optimal position (Spearman rho r = -0.34, P = 0.015). Those with optimal positioning had a 16% incidence of P-PM relative to 48% of those with suboptimal positioning (Pearson chi(2) P = 0.015). The incidence of P-PM following TAVI with the Corevalve bioprosthesis is compared favourably with that seen after AVR with conventional open stented bioprostheses and its occurrence is influenced by device positioning.

  18. Variable stiffness and damping MR isolator

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X Z; Wang, X Y; Li, W H; Kostidis, K [University of Wollongong, School of Mechanical, Materials and Mechatronic Engineering, NSW 2522 (Australia)], E-mail: weihuali@uow.edu.au

    2009-02-01

    This paper presents the development of a magnetorheological (MR) fluid-based variable stiffness and damping isolator for vibration suppressions. The MR fluid isolator used a sole MR control unit to achieve the variable stiffness and damping in stepless and relative large scope. A mathematical model of the isolator was derived, and a prototype of the MR fluid isolator was fabricated and its dynamic behavior was measured in vibration under various applied magnetic fields. The parameters of the model under various magnetic fields were identified and the dynamic performances of isolator were evaluated.

  19. Successful resuscitation from two cardiac arrests in a female patient with critical aortic stenosis, severe mitral regurgitation and coronary artery disease

    Directory of Open Access Journals (Sweden)

    Mijušković Dragan

    2012-01-01

    Full Text Available Introduction. The incidence of sudden cardiac death in patients with severe symptomatic aortic stenosis is up to 34% and resuscitation is described as highly unsuccessful. Case report. A 72-year-old female patient with severe aortic stenosis combined with severe mitral regurgitation and three-vessel coronary artery disease was successfully resuscitated following two in-hospital cardiac arrests. The first cardiac arrest occurred immediately after intraarterial injection of low osmolar iodinated agent during coronary angiography. Angiography revealed 90% occlusion of the proximal left main coronary artery and circumflex branch. The second arrest followed induction of anesthesia. Following successful open-chest resuscitation, aortic valve replacement, mitral valvuloplasty and three-vessel aortocoronary bypass were performed. Postoperative pericardial tamponade required surgical revision. The patient recovered completely. Conclusion. Decision to start resuscitation may be justified in selected patients with critical aortic stenosis, even though cardiopulmonary resuscitation in such cases is generally considered futile.

  20. [Supra-aortic trunks occlusive disease: three different treatment approaches].

    Science.gov (United States)

    Dias, P; Almeida, P; Sampaio, S; Silva, A; Leite-Moreira, A; Pinho, P; Roncon de Albuquerque, R

    2010-01-01

    Unlike carotid bifurcation atherosclerotic stenosis, supra-aortic trunks (SAT) occlusive disease is rare and its revascularization uncommon, accouting for less than 10% of the operations performed on the extracranial brain-irrigating arteries. There are three different treatment approaches: transthoracic, extra-anatomic cervical and endovascular. Endovascular repair is gaining popularity as first-line therapy for proximal lesions with favorable anatomy because of its low morbidity and rare mortality. Extra-anatomic bypass is a safe and durable reconstruction and should be considered in patients with single vessel disease, with cardiopulmonary high-risk or with limited life expectancy. If cardiac surgery is needed, central transthoracic reconstruction is preferable, and the two procedures should be combined. The long-term patency of bypasses with aortic origin, specially when multiple vessels are involved, is superior to other repair techniques. We present three clinical cases that illustrate each of these therapeutic strategies: central brachiocephalic revascularization and synchronous cardiac surgery in a patient with complex SAT atherosclerosis disease; subclavian-carotid transposition for disabling upper limb claudication; and subclavian artery stenting for subclavian-steal syndrome. Surgical approach selection should be based on the individual patient's anatomy and operative risk.

  1. Early results of valve-sparing ascending aortic replacement in type A aortic dissection and aortic insufficiency

    Directory of Open Access Journals (Sweden)

    М. Л. Гордеев

    2016-08-01

    Full Text Available Aim: The study was designed to investigate predictors of effective valve-sparing ascending aortic replacement in patients with Stanford type A aortic dissection combined with aortic insufficiency and to analyze efficacy and safety of this kind of surgery.Methods: From January 2010 to December 2015, 49 patients with Stanford type A aortic dissection combined with aortic insufficiency underwent ascending aortic replacement. All patients were divided into 3 groups: valve-sparing procedures (group 1, n = 11, combined aortic valve and supracoronary ascending aortic replacement (group 2, n = 12, and Bentall procedure (group 3, n = 26. We assessed the initial status of patients, incidence of complications and efficacy of valve-sparing ascending aortic replacement.Results: The hospital mortality rate was 8.2% (4/49 patients. The amount of surgical correction correlated with the initial diameter of the aorta at the level of the sinuses of Valsalva. During the hospital period, none of patients from group 1 developed aortic insufficiency exceeding Grade 2 and the vast majority of patients had trivial aortic regurgitation. The parameters of cardiopulmonary bypass, cross-clamp time and circulatory arrest time did not correlate with the initial size of the ascending aorta and aortic valve blood flow impairment, neither did they influence significantly the incidence and severity of neurological complications. The baseline size of the ascending aorta and degree of aortic regurgitation did not impact the course of the early hospital period.Conclusions: Supracoronary ascending aortic replacement combined with aortic valve repair in ascending aortic dissection and aortic regurgitation is effective and safe. The initial size of the ascending aorta and aortic arch do not influence immediate results. The diameter of the aorta at the level of the sinuses of Valsalva and the condition of aortic valve leaflets could be considered as the limiting factors. Further long

  2. Aortic elongation in aortic aneurysm and dissection: the Tübingen Aortic Pathoanatomy (TAIPAN) project.

    Science.gov (United States)

    Krüger, Tobias; Sandoval Boburg, Rodrigo; Lescan, Mario; Oikonomou, Alexandre; Schneider, Wilke; Vöhringer, Luise; Lausberg, Henning; Bamberg, Fabian; Blumenstock, Gunnar; Schlensak, Christian

    2018-01-24

    To study the lengths and diameters of aortic segments in healthy and diseased aortas and to assess the role of aortic elongation in Type A aortic dissection (TAD) prediction. Ectasia and aneurysm were defined by ascending aorta diameters of 45-54 mm and ≥55 mm, respectively. Computed tomography angiography studies of 256 healthy, 102 ectasia, 38 aneurysm, 17 pre-TAD and 166 TAD aortas were analysed using curved multiplanar reformats. The study groups were structurally equal. The diameter of the ascending aorta was 35 mm in the control group and was larger (P TAD (43 mm) and TAD (56 mm) groups. The length of the ascending aorta from the aortic annulus to the brachiocephalic trunk was 92 mm in the control group, 113 mm in the ectasia group, 120 mm in the aneurysm group and 111 mm and 118 mm in the pre-TAD and TAD groups (all P TAD group and 48% of the TAD group. The correlation between the diameter and the length of the ascending aorta was r = 0.752; therefore, both parameters must be examined separately. A score considering both parameters identified 23.5% of pre-TAD patients, significantly more than the diameter alone, and 31.4% of ectasia aortas were elongated. Patients with ectatic (45-54 mm diameter) and elongated (≥120 mm) ascending aortas represent a high-risk subpopulation for TAD. © The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  3. LSODE, 1. Order Stiff or Non-Stiff Ordinary Differential Equations System Initial Value Problems

    International Nuclear Information System (INIS)

    Hindmarsh, A.C.; Petzold, L.R.

    2005-01-01

    1 - Description of program or function: LSODE (Livermore Solver for Ordinary Differential Equations) solves stiff and non-stiff systems of the form dy/dt = f. In the stiff case, it treats the Jacobian matrix df/dy as either a dense (full) or a banded matrix, and as either user-supplied or internally approximated by difference quotients. It uses Adams methods (predictor-corrector) in the non-stiff case, and Backward Differentiation Formula (BDF) methods (the Gear methods) in the stiff case. The linear systems that arise are solved by direct methods (LU factor/solve). The LSODE source is commented extensively to facilitate modification. Both a single-precision version and a double-precision version are available. 2 - Methods: It is assumed that the ODEs are given explicitly, so that the system can be written in the form dy/dt = f(t,y), where y is the vector of dependent variables, and t is the independent variable. LSODE contains two variable-order, variable- step (with interpolatory step-changing) integration methods. The first is the implicit Adams or non-stiff method, of orders one through twelve. The second is the backward differentiation or stiff method (or BDF method, or Gear's method), of orders one through five. 3 - Restrictions on the complexity of the problem: The differential equations must be given in explicit form, i.e., dy/dt = f(y,t). Problems with intermittent high-speed transients may cause inefficient or unstable performance

  4. Use of Suture-Mediated Closure Device in Percutaneous Direct Carotid Puncture During Chimney-Thoracic Endovascular Aortic Repair

    International Nuclear Information System (INIS)

    Chan, Gabriel; Quek, Lawrence Hwee Han; Tan, Glenn Leong Wei; Pua, Uei

    2016-01-01

    BackgroundInsertion of a carotid chimney graft during thoracic endovascular aortic repair (Ch-TEVAR) is a recognized technique to extend the proximal landing zone into the aortic arch in the treatment of thoracic aortic disease. Conventional technique requires surgical exposure of the carotid artery for insertion of the carotid chimney graft.MethodologyWe describe our experience in the use of a suture-mediated closure device in percutaneous Ch-TEVAR in four patients.ResultsSuccessful hemostasis was achieved in all four patients. No complications related to the carotid puncture were recorded.ConclusionWe conclude that using suture-mediated closure device for carotid closure appears feasible and deserves further studies as a potential alternative to conventional surgical approach.

  5. Use of Suture-Mediated Closure Device in Percutaneous Direct Carotid Puncture During Chimney-Thoracic Endovascular Aortic Repair

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Gabriel, E-mail: dr.changabriel@gmail.com; Quek, Lawrence Hwee Han, E-mail: lawrence-quek@ttsh.com.sg [Tan Tock Seng Hospital, Department of Diagnostic Radiology (Singapore); Tan, Glenn Leong Wei, E-mail: glenn-tan@ttsh.com.sg [Tan Tock Seng Hospital, Department of General Surgery (Singapore); Pua, Uei, E-mail: druei@yahoo.com [Tan Tock Seng Hospital, Department of Diagnostic Radiology (Singapore)

    2016-07-15

    BackgroundInsertion of a carotid chimney graft during thoracic endovascular aortic repair (Ch-TEVAR) is a recognized technique to extend the proximal landing zone into the aortic arch in the treatment of thoracic aortic disease. Conventional technique requires surgical exposure of the carotid artery for insertion of the carotid chimney graft.MethodologyWe describe our experience in the use of a suture-mediated closure device in percutaneous Ch-TEVAR in four patients.ResultsSuccessful hemostasis was achieved in all four patients. No complications related to the carotid puncture were recorded.ConclusionWe conclude that using suture-mediated closure device for carotid closure appears feasible and deserves further studies as a potential alternative to conventional surgical approach.

  6. Endo-luminal grafting for treatment of abdominal aortic aneurysms

    International Nuclear Information System (INIS)

    Fu Weiguo; Wang Yuqi; Chen Fuzhen; Ye Jianrong; Wang Jianhua; Yan Zhiping; Cheng Jiemin

    2000-01-01

    Objective: To evaluate the preliminary clinical results of endovascular procedures for abdominal aortic aneurysms (AAA) in a prospective study. Methods: Six patients (average age 70 years, range 56 to 78) with infrarenal AAA were enrolled in Shanghai Zhongshan hospital from February 1998 to February 1999. Computed tomography and angiography were done in every patient for measurement of the length, diameter, and angulation of the proximal and distal AAA necks, aneurysm sac, and common and external iliac arteries. The average diameter of the aneurysm was 6.3 cm (range 4.6 cm to 8.0 cm). The mean proximal neck diameter was 2.0 cm (range 1.8 cm to 2.2 cm) and proximal neck length was 3.0 cm (range 2.5 cm to 3.5 cm). All patients were treated with the endo-luminal grafting for exclusion of AAA. Results: Two tubular and 4 bifurcated endo-grafts were used. All endo-graft procedures were completed successfully. One patient died of renal failure 72 hours after the procedure because of the prolonged operative time and excessive contrast medium. Aortography after the procedure showed the AAA were excluded by endo-graft and no endo-leak in the proximal or distal connections was detected. The patients could take meal and were ambulatory on the first and second postoperative day, respectively. Clinical success (aneurysm exclusion with no death or endo-leak) at 30 days was 83.3%. In the 24 months follow-up in 5 cases, no migration, endo-leak, and increasing aneurysm size were detected with spiral CT or color Duplex ultrasound. Conclusion: Based on initial results and a short term mean follow-up period of 24 months, the endovascular treatment of AAA with stent-graft system is feasible and safe. Further study will be required to observe the long term result in the exclusion of AAA

  7. Infected aortic aneurysm and inflammatory aortic aneurysm. In search of an optimal differential diagnosis

    International Nuclear Information System (INIS)

    Ishizaka, Nobukazu; Sohmiya, Koichi; Miyamura, Masatoshi; Umeda, Tatsuya; Tsuji, Motomu; Katsumata, Takahiro; Miyata, Tetsuro

    2012-01-01

    Infected aortic aneurysm and inflammatory aortic aneurysm each account for a minor fraction of the total incidence of aortic aneurysm and are associated with periaortic inflammation. Despite the similarity, infected aortic aneurysm generally shows a more rapid change in clinical condition, leading to a fatal outcome; in addition, delayed diagnosis and misuse of corticosteroid or immunosuppressing drugs may lead to uncontrolled growth of microorganisms. Therefore, it is mandatory that detection of aortic aneurysm is followed by accurate differential diagnosis. In general, infected aortic aneurysm appears usually as a saccular form aneurysm with nodularity, irregular configuration; however, the differential diagnosis may not be easy sometimes for the following reasons: symptoms, such as abdominal and/or back pain and fever, and blood test abnormalities, such as elevated C-reactive protein and enhanced erythrocyte sedimentation rate, are common in infected aortic aneurysm, but they are not found infrequently in inflammatory aortic aneurysm; some inflammatory aortic aneurysms are immunoglobulin (Ig) G4-related, but not all of them; the prevalence of IgG4 positivity in infected aortic aneurysm has not been well investigated; enhanced uptake of 18F-fluorodeoxyglucose (FDG) by 18F-FDG-positron emission tomography may not distinguish between inflammation mediated by autoimmunity and that mediated by microorganism infection. Here we discuss the characteristics of these two forms of aortic aneurysm and the points of which we have to be aware before reaching a final diagnosis. (author)

  8. Delayed Presentation of a Giant Ascending Aortic Aneurysm following Aortic Valve Replacement

    Directory of Open Access Journals (Sweden)

    Tugrul Göncü

    2009-01-01

    Full Text Available Giant ascending aortic aneurysm formation following aortic valve replacement is rare. A 28-year-old man who underwent aortic valve replacement with a prosthetic valve for aortic regurgitation secondary to congenital bicuspid aortic valve about 10 years ago was diagnosed with a giant ascending aortic aneurysm about 16 cm in diameter in follow-up. The aneurysm was resected leaving the functional old mechanical prosthesis in place and implanted a 34-mm Hemashield woven graft, associated with the left and right coronary artery button implantation. Histological findings of the aortic aneurysm wall showed cystic medial necrosis. The postoperative course was uneventful and postoperative examination demonstrated good surgical results.

  9. Early Results of the PETTICOAT Technique for the Management of Acute Type A Aortic Dissection.

    Science.gov (United States)

    Kotha, Vamshi Krishna; Pozeg, Zlatko I; Herget, Eric J; Moon, Michael C; Appoo, Jehangir J

    2017-08-01

    Conventional surgical techniques for acute Type A aortic dissection (ATAAD) generally fail to address residual dissection in the descending aorta. The persistence of a false lumen is associated with visceral malperfusion in the acute setting and adverse aortic remodeling in the chronic setting. Hybrid aortic arch repair techniques may improve perioperative and long-term mortality by expanding the true lumen and obliterating the false lumen. However, there is a limit to the extent of aortic coverage due to the concomitant risk of spinal cord ischemia. In Type B dissection, the PETTICOAT (Provisional Extension To Induce Complete Attachment) technique, which entails stent graft coverage of the primary intimal tear followed by bare metal stent placement distally, may improve true lumen caliber and promote false lumen thrombosis without increasing the risk of spinal cord ischemia, as intercostal branches remain perfused through the bare metal stents. The technique of hybrid arch with surgical creation of a Dacron landing zone covering a stent graft in the proximal descending aorta and bare metal stents in the thoraco-abdominal aorta is a promising concept in the treatment of ATAAD.

  10. Altered arterial stiffness and subendocardial viability ratio in young healthy light smokers after acute exercise.

    Directory of Open Access Journals (Sweden)

    Robert J Doonan

    Full Text Available Studies showed that long-standing smokers have stiffer arteries at rest. However, the effect of smoking on the ability of the vascular system to respond to increased demands (physical stress has not been studied. The purpose of this study was to estimate the effect of smoking on arterial stiffness and subendocardial viability ratio, at rest and after acute exercise in young healthy individuals.Healthy light smokers (n = 24, pack-years = 2.9 and non-smokers (n = 53 underwent pulse wave analysis and carotid-femoral pulse wave velocity measurements at rest, and 2, 5, 10, and 15 minutes following an exercise test to exhaustion. Smokers were tested, 1 after 12h abstinence from smoking (chronic condition and 2 immediately after smoking one cigarette (acute condition. At rest, chronic smokers had higher augmentation index and lower aortic pulse pressure than non-smokers, while subendocardial viability ratio was not significantly different. Acute smoking increased resting augmentation index and decreased subendocardial viability ratio compared with non-smokers, and decreased subendocardial viability ratio compared with the chronic condition. After exercise, subendocardial viability ratio was lower, and augmentation index and aortic pulse pressure were higher in non-smokers than smokers in the chronic and acute conditions. cfPWV rate of recovery of was greater in non-smokers than chronic smokers after exercise. Non-smokers were also able to achieve higher workloads than smokers in both conditions.Chronic and acute smoking appears to diminish the vascular response to physical stress. This can be seen as an impaired 'vascular reserve' or a blunted ability of the blood vessels to accommodate the changes required to achieve higher workloads. These changes were noted before changes in arterial stiffness or subendocardial viability ratio occurred at rest. Even light smoking in young healthy individuals appears to have harmful effects on vascular

  11. Outcome-based anatomic criteria for defining the hostile aortic neck.

    Science.gov (United States)

    Jordan, William D; Ouriel, Kenneth; Mehta, Manish; Varnagy, David; Moore, William M; Arko, Frank R; Joye, James; de Vries, Jean-Paul P M

    2015-06-01

    There is abundant evidence linking hostile proximal aortic neck anatomy to poor outcome after endovascular aortic aneurysm repair (EVAR), yet the definition of hostile anatomy varies from study to study. This current analysis was undertaken to identify anatomic criteria that are most predictive of success or failure at the aortic neck after EVAR. The study group comprised 221 patients in the Aneurysm Treatment using the Heli-FX Aortic Securement System Global Registry (ANCHOR) clinical trial, a population enriched with patients with challenging aortic neck anatomy and failure of sealing. Imaging protocols were not protocol specified but were performed according to the institution's standard of care. Core laboratory analysis assessed the three-dimensional centerline-reformatted computed tomography scans. Failure at the aortic neck was defined by type Ia endoleak occurring at the time of the initial endograft implantation or during follow-up. Receiver operating characteristic curve analysis was used to assess the value of each anatomic measure in the classification of aortic neck success and failure and to identify optimal thresholds of discrimination. Binary logistic regression was performed after excluding highly intercorrelated variables, creating a final model with significant predictors of outcome after EVAR. Among the 221 patients, 121 (54.8%) remained free of type Ia endoleak and 100 (45.2%) did not. Type Ia endoleaks presented immediately after endograft deployment in 58 (58.0%) or during follow-up in 42 (42.0%). Receiver operating characteristic curve analysis identified 12 variables where the classification of patients with type Ia endoleak was significantly more accurate than chance alone. Increased aortic neck diameter at the lowest renal artery (P = .013) and at 5 mm (P = .008), 10 mm (P = .008), and 15 mm (P = .010) distally; aneurysm sac diameter (P = .001), common iliac artery diameters (right, P = .012; left, P = .032), and a conical (P = .049) neck

  12. Elastin in large artery stiffness and hypertension

    Science.gov (United States)

    Wagenseil, Jessica E.; Mecham, Robert P.

    2012-01-01

    Large artery stiffness, as measured by pulse wave velocity (PWV), is correlated with high blood pressure and may be a causative factor in essential hypertension. The extracellular matrix components, specifically the mix of elastin and collagen in the vessel wall, determine the passive mechanical properties of the large arteries. Elastin is organized into elastic fibers in the wall during arterial development in a complex process that requires spatial and temporal coordination of numerous proteins. The elastic fibers last the lifetime of the organism, but are subject to proteolytic degradation and chemical alterations that change their mechanical properties. This review discusses how alterations in the amount, assembly, organization or chemical properties of the elastic fibers affect arterial stiffness and blood pressure. Strategies for encouraging or reversing alterations to the elastic fibers are addressed. Methods for determining the efficacy of these strategies, by measuring elastin amounts and arterial stiffness, are summarized. Therapies that have a direct effect on arterial stiffness through alterations to the elastic fibers in the wall may be an effective treatment for essential hypertension. PMID:22290157

  13. Diagram of state of stiff amphiphilic macromolecules

    NARCIS (Netherlands)

    Markov, Vladimir A.; Vasilevskaya, Valentina V.; Khalatur, Pavel G.; ten Brinke, Gerrit; Khokhlov, Alexei R.

    2007-01-01

    We studied coil-globule transitions in stiff-chain amphiphilic macromolecules via computer modeling and constructed phase diagrams for such molecules in terms of solvent quality and persistence length. We showed that the shape of the phase diagram essentially depends on the macromolecule degree of

  14. Advanced damper with negative structural stiffness elements

    International Nuclear Information System (INIS)

    Dong, Liang; Lakes, Roderic S

    2012-01-01

    Negative stiffness is understood as the occurrence of a force in the same direction as the imposed deformation. Structures and composites with negative stiffness elements enable a large amplification in damping. It is shown in this work, using an experimental approach, that when a flexible flat-ends column is aligned in a post-buckled condition, a negative structural stiffness and large hysteresis (i.e., high damping) can be achieved provided the ends of the column undergo tilting from flat to edge contact. Stable axial dampers with initial modulus equivalent to that of the parent material and with enhanced damping were designed and built using constrained negative stiffness effects entailed by post-buckled press-fit flat-ends columns. Effective damping of approximately 1 and an effective stiffness–damping product of approximately 1.3 GPa were achieved in such stable axial dampers consisting of PMMA columns. This is a considerable improvement for this figure of merit (i.e., the stiffness–damping product), which generally cannot exceed 0.6 GPa for currently used damping layers. (paper)

  15. Transcatheter Aortic Valve Replacement in Europe

    DEFF Research Database (Denmark)

    Mylotte, Darren; Osnabrugge, Ruben L J; Windecker, Stephan

    2013-01-01

    The authors sought to examine the adoption of transcatheter aortic valve replacement (TAVR) in Western Europe and investigate factors that may influence the heterogeneous use of this therapy.......The authors sought to examine the adoption of transcatheter aortic valve replacement (TAVR) in Western Europe and investigate factors that may influence the heterogeneous use of this therapy....

  16. Graft infections after surgical aortic reconstructions

    NARCIS (Netherlands)

    Berger, P.

    2015-01-01

    Prosthetic vascular grafts are frequently used to reconstruct (part) of the aorta. Every surgical procedure caries a certain risk for infection and when a prosthetic aortic graft is implanted, this may lead to an aortic graft infection (AGI). Endovascular techniques have gradually replaced open

  17. Severe aortic stenosis: diagnosis, treatment and prognosis

    NARCIS (Netherlands)

    M.W.A. van Geldorp (Martijn)

    2013-01-01

    textabstractDegenerative aortic stenosis is the most common valvular heart disease in developed countries. The prevalence of severe aortic stenosis increases with age from 1% in people below 65 years of age to nearly 6% in people over the age of 85. Since the population life expectancy continues to

  18. Valve-sparing aortic root replacement†

    NARCIS (Netherlands)

    Koolbergen, David R.; Manshanden, Johan S. J.; Bouma, Berto J.; Blom, Nico A.; Mulder, Barbara J. M.; de Mol, Bas A. J. M.; Hazekamp, Mark G.

    2015-01-01

    To evaluate our results of valve-sparing aortic root replacement and associated (multiple) valve repair. From September 2003 to September 2013, 97 patients had valve-sparing aortic root replacement procedures. Patient records and preoperative, postoperative and recent echocardiograms were reviewed.

  19. Parametric study of roof diaphragm stiffness requirements

    International Nuclear Information System (INIS)

    Jones, W.D.; Tenbus, M.A.

    1991-01-01

    A common assumption made in performing a dynamic seismic analysis for a building is that the roof/floor system is open-quotes rigidclose quotes. This assumption would appear to be reasonable for many of the structures found in nuclear power plants, since many of these structures are constructed of heavily reinforced concrete having floor/roof slabs at least two feet in thickness, and meet the code requirements for structural detailing for seismic design. The roofs of many Department of Energy (DOE) buildings at the Oak Ridge Y-12 Plant in Oak Ridge, Tennessee, have roofs constructed of either metal, precast concrete or gypsum plank deck overlaid with rigid insulation, tar and gravel. In performing natural phenomena hazard assessments for one such facility, it was assumed that the existing roof performed first as a flexible diaphragm (zero stiffness) and then, rigid (infinitely stiff). For the flexible diaphragm model it was determined that the building began to experience significant damage around 0.09 g's. For the rigid diaphragm model it was determined that no significant damage was observed below 0.20 g's. A Conceptual Design Report has been prepared for upgrading/replacing the roof of this building. The question that needed to be answered here was, open-quotes How stiff should the new roof diaphragm be in order to satisfy the rigid diaphragm assumption and, yet, be cost effective?close quotes. This paper presents a parametric study of a very simple structural system to show that the design of roof diaphragms needs to consider both strength and stiffness (frequency) requirements. This paper shows how the stiffness of a roof system affects the seismically induced loads in the lateral, vertical load resisting elements of a building and provides guidance in determining how open-quotes rigidclose quotes a roof system should be in order to accomplish a cost effective design

  20. Endovascular Treatment of Infrarenal Abdominal Aortic Aneurysm with Short and Angulated Neck in High-Risk Patient

    Directory of Open Access Journals (Sweden)

    Stylianos Koutsias

    2013-01-01

    Full Text Available Endovascular treatment of abdominal aortic aneurysms (AAA is an established alternative to open repair. However lifelong surveillance is still required to monitor endograft function and signal the need for secondary interventions (Hobo and Buth 2006. Aortic morphology, especially related to the proximal neck, often complicates the procedure or increases the risk for late device-related complications (Hobo et al. 2007 and Chisci et al. 2009. The definition of a short and angulated neck is based on length (60° (Hobo et al. 2007 and Chisci et al. 2009. A challenging neck also offers difficulties during open repairs (OR, necessitating extensive dissection with juxta- or suprarenal aortic cross-clamping. Patients with extensive aneurysmal disease typically have more comorbidities and may not tolerate extensive surgical trauma (Sarac et al. 2002. It is, therefore, unclear whether aneurysms with a challenging proximal neck should be offered EVAR or OR (Cox et al. 2006, Choke et al. 2006, Robbins et al. 2005, Sternbergh III et al. 2002, Dillavou et al. 2003, and Greenberg et al. 2003. In our case the insertion of a thoracic endograft followed by the placement of a bifurcated aortic endograft for the treatment of a very short and severely angulated neck proved to be feasible offering acceptable duration of aneurysm exclusion. This adds up to our armamentarium in the treatment of high-risk patients, and it should be considered in emergency cases when the fenestrated and branched endografts are not available.

  1. Mechanical, structural, and dynamical modifications of cholesterol exposed porcine aortic elastin.

    Science.gov (United States)

    Bilici, Kubra; Morgan, Steven W; Silverstein, Moshe C; Wang, Yunjie; Sun, Hyung Jin; Zhang, Yanhang; Boutis, Gregory S

    2016-11-01

    Elastin is a protein of the extracellular matrix that contributes significantly to the elasticity of connective tissues. In this study, we examine dynamical and structural modifications of aortic elastin exposed to cholesterol by NMR spectroscopic and relaxation methodologies. Macroscopic measurements are also presented and reveal that cholesterol treatment may cause a decrease in the stiffness of tissue. 2 H NMR relaxation techniques revealed differences between the relative populations of water that correlate with the swelling of the tissue following cholesterol exposure. 13 C magic-angle-spinning NMR spectroscopy and relaxation methods indicate that cholesterol treated aortic elastin is more mobile than control samples. Molecular dynamics simulations on a short elastin repeat VPGVG in the presence of cholesterol are used to investigate the energetic and entropic contributions to the retractive force, in comparison to the same peptide in water. Peptide stiffness is observed to reduce following cholesterol exposure due to a decrease in the entropic force. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Fixation and mounting of porcine aortic valves for use in mock circuits.

    Science.gov (United States)

    Schlöglhofer, Thomas; Aigner, Philipp; Stoiber, Martin; Schima, Heinrich

    2013-10-01

    Investigations of the circulatory system in vitro use mock circuits that require valves to mimic the cardiac situation. Whereas mechanical valves increase water hammer effects due to inherent stiffness and do not allow the use of pressure lines or catheters, bioprosthetic valves are expensive and of limited durability in test fluids. Therefore, we developed a cheap, fast, alternative method to mount valves obtained from the slaughterhouse in mock circuits. Porcine aortic roots were obtained from the abattoir and used either in native condition or after fixation. Fixation was performed at a constant retrograde pressure to ensure closed valve position. Fixation time was 4 h in a 0.5%-glutaraldehyde phosphate buffer. The fixed valves were molded into a modular mock circulation connector using a fast curing silicone. Valve functionality was evaluated in a pulsatile setting (cardiac output = 4.7 l/min, heart rate = 80 beats/min) and compared before and after fixation. Leaflet motion was recorded with a high-speed camera and valve insufficiency was quantified by leakage flow under steady pressure application (80 mmHg). Under physiological conditions the aortic valves showed almost equal leaflet motion in native and fixed conditions. However, the leaflets of the native valves showed lower stiffness and more fluttering during systole than the fixed specimens. Under retrograde pressure, fresh and fixed valves showed small leakage flows of <30 ml/min. The new mounting and fixation procedure is a fast method to fabricate low cost biologic valves for the use in mock circuits.

  3. MRI evaluation of the aortic disease

    International Nuclear Information System (INIS)

    Kapuscinski, O.; Polkowski, J.; Zaleska, T.; Walecki, J.; Biesiadko, M.

    1994-01-01

    The goal of our study was to establish the value of MRI in diagnosing aortic disease. During 3 years period 46 patients were examined (12 women aged from 6 to 62 years and 34 men aged from 8 to 72 years). In 28 cases the thoracic aorta was examined, in 6 cases the abdominal aorta and in 12 - both the thoracic and the abdominal aorta. MR images were performed on MRT 50 A Toshiba unit 0.5 T. MR images demonstrated aortic aneurysm (caused by atherosclerosis or trauma), aortic dissections, aortic anomalies (i.e. in Turner syndrome) and non-specific aortitis and vasculitis. We regard MRI as preferable noninvasive imaging technique in diagnosing aortic disease. (author)

  4. ProxImaL: efficient image optimization using proximal algorithms

    KAUST Repository

    Heide, Felix

    2016-07-11

    Computational photography systems are becoming increasingly diverse, while computational resources-for example on mobile platforms-are rapidly increasing. As diverse as these camera systems may be, slightly different variants of the underlying image processing tasks, such as demosaicking, deconvolution, denoising, inpainting, image fusion, and alignment, are shared between all of these systems. Formal optimization methods have recently been demonstrated to achieve state-of-the-art quality for many of these applications. Unfortunately, different combinations of natural image priors and optimization algorithms may be optimal for different problems, and implementing and testing each combination is currently a time-consuming and error-prone process. ProxImaL is a domain-specific language and compiler for image optimization problems that makes it easy to experiment with different problem formulations and algorithm choices. The language uses proximal operators as the fundamental building blocks of a variety of linear and nonlinear image formation models and cost functions, advanced image priors, and noise models. The compiler intelligently chooses the best way to translate a problem formulation and choice of optimization algorithm into an efficient solver implementation. In applications to the image processing pipeline, deconvolution in the presence of Poisson-distributed shot noise, and burst denoising, we show that a few lines of ProxImaL code can generate highly efficient solvers that achieve state-of-the-art results. We also show applications to the nonlinear and nonconvex problem of phase retrieval.

  5. Treatment strategy for ruptured abdominal aortic aneurysms.

    Science.gov (United States)

    Davidovic, L

    2014-07-01

    Rupture is the most serious and lethal complication of the abdominal aortic aneurysm. Despite all improvements during the past 50 years, ruptured abdominal aortic aneurysms are still associated with very high mortality. Namely, including patients who die before reaching the hospital, the mortality rate due to abdominal aortic aneurysm rupture is 90%. On the other hand, during the last twenty years, the number of abdominal aortic aneurysms significantly increased. One of the reasons is the fact that in majority of countries the general population is older nowadays. Due to this, the number of degenerative AAA is increasing. This is also the case for patients with abdominal aortic aneurysm rupture. Age must not be the reason of a treatment refusal. Optimal therapeutic option ought to be found. The following article is based on literature analysis including current guidelines but also on my Clinics significant experience. Furthermore, this article show cases options for vascular medicine in undeveloped countries that can not apply endovascular procedures at a sufficient level and to a sufficient extent. At this moment the following is evident. Thirty-day-mortality after repair of ruptured abdominal aortic aneurysms is significantly lower in high-volume hospitals. Due to different reasons all ruptured abdominal aortic aneurysms are not suitable for EVAR. Open repair of ruptured abdominal aortic aneurysm should be performed by experienced open vascular surgeons. This could also be said for the treatment of endovascular complications that require open surgical conversion. There is no ideal procedure for the treatment of AAA. Each has its own advantages and disadvantages, its own limits and complications, as well as indications and contraindications. Future reductions in mortality of ruptured abdominal aortic aneurysms will depend on implementation of population-based screening; on strategies to prevent postoperative organ injury and also on new medical technology

  6. [Modern aortic surgery in Marfan syndrome--2011].

    Science.gov (United States)

    Kallenbach, K; Schwill, S; Karck, M

    2011-09-01

    Marfan syndrome is a hereditary disease with a prevalence of 2-3 in 10,000 births, leading to a fibrillin connective tissue disorder with manifestations in the skeleton, eye, skin, dura mater and in particular the cardiovascular system. Since other syndromes demonstrate similar vascular manifestations, but therapy may differ significantly, diagnosis should be established using the revised Ghent nosology in combination with genotypic analysis in specialized Marfan centres. The formation of aortic root aneurysms with the subsequent risk of acute aortic dissection type A (AADA) or aortic rupture limits life expectancy in patients with Marfan syndrome. Therefore, prophylactic replacement of the aortic root needs to be performed before the catastrophic event of AADA can occur. The goal of surgery is the complete resection of pathological aortic tissue. This can be achieved with excellent results by using a (mechanically) valved conduit that replaces both the aortic valve and the aortic root (Bentall operation). However, the need for lifelong anticoagulation with Coumadin can be avoided using the aortic valve sparing reimplantation technique according to David. The long-term durability of the reconstructed valve is favourable, and further technical improvements may improve longevity. Although results of prospective randomised long-term studies comparing surgical techniques are lacking, the David operation has become the surgical method of choice for aortic root aneurysms, not only at the Heidelberg Marfan Centre. Replacement of the aneurysmal dilated aortic arch is performed under moderate hypothermic circulatory arrest combined with antegrade cerebral perfusion using a heart-lung machine, which we also use in thoracic or thoracoabdominal aneurysms. Close post-operative follow-up in a Marfan centre is pivotal for the early detection of pathological changes on the diseased aorta.

  7. MR imaging of aortic coarctation

    International Nuclear Information System (INIS)

    Beslic, S.

    2004-01-01

    Purpose. The purpose of this paper is to analyse the contribution of MRI as diagnostic procedure in the preoperative diagnosis of aortic coarctation (CoA), in patients with clinical and echocardiographic suspicion for this disease. Patients and methods. During the period of three years, eight patients were examined, 5 (62.5%) male and 3 (37.5%) female patients with clinical echocardiographic suspicion of CoA. The ratio between male and female patients was 1.7 : 1. The youngest patient was 3 and the oldest 46 years (median age was 15 years). Without administration of contrast media and using body coil the examinations were performed with MR machine Magnetom 1.0 Tesla ( S iemens ) , with the slice thickness of 6 mm, Fast spin-echo (FSE) T1W sequences, Cine gradient echo (GRE) sequence with slab 7 mm and time of flight (TOF) sequence with MIP reconstructions were applied. During the examinations the patients underwent also ECG gating. Examinations were done in axial, coronal and oblique sagittal projections with measuring of the dimensions of cardiovascular structures. Results. CoA was found in 8 (100%) patients. In 7 (87.5%) cases, coarctation developed at isthmus and in one case, coarctation was detected at the horizontal part of aortic arch, between the truncus arteriosus of the left carotid communis artery. Aortal insufficiency was found in 7 (87.5%) patients; in four of them (50%), bicuspidia was confirmed (bicuspid aortic valve), 7 (87.5%) patients had slightly expressed hypertrophy of the left ventricle. Two (25%) patients had dilatation of the ascendant aorta, six (75%) wider outgoing vessels of the aortic arch, four (50%) had well developed arterial collaterals and 2 (25%) patients rib notching. In 2 (25%) patients as side finding thymus persistent was found. Average diameter of coarctation was 10 mm. In one patient, CoA was accompanied with stenosis of pulmonary artery, in one with ventricular septal defect, and one with tricuspid insufficiency. The results

  8. Mixed, Nonsplit, Extended Stability, Stiff Integration of Reaction Diffusion Equations

    KAUST Repository

    Alzahrani, Hasnaa H.

    2016-01-01

    A tailored integration scheme is developed to treat stiff reaction-diffusion prob- lems. The construction adapts a stiff solver, namely VODE, to treat reaction im- plicitly together with explicit treatment of diffusion. The second-order Runge

  9. Imaging techniques in aortic valve and root surgery

    NARCIS (Netherlands)

    Regeer, M.V.

    2017-01-01

    Aortic valve sparing surgery for aortic regurgitation and/or aortopathy serves as an alternative to aortic valve and root replacement. One of the advantages of aortic valve sparing surgery over conventional replacement is that there is no need for life-long anticoagulation, which is particularly

  10. Suprarenal fixation resulting in intestinal malperfusion after endovascular aortic aneurysm repair.

    Science.gov (United States)

    Siani, Andrea; Accrocca, Federico; De Vivo, Gennaro; Marcucci, Giustino

    2016-05-01

    Superior mesenteric artery (SMA) and coeliac axis (CA) occlusion after endovascular abdominal aneurysm aortic repair (EVAR-AAA), using endograft with suprarenal fixation, are uncommon. However, we are reporting a case of visceral malperfusion, which occurred 7 days after successful EVAR with suprarenal fixation for symptomatic AAA. Endograft metal stent barbs caused severe stenosis of SMA and CA. A successful recovery of SMA was carried out by means of a balloon-expandable stent released through bare metal stent barbs. We believe that an unfavourable anatomy of a proximal aortic neck and visceral aorta may have caused a wrong stent strut deployment with the coverage of CA and SMA. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  11. Correction of aortic insufficiency with an external adjustable prosthetic aortic ring.

    Science.gov (United States)

    Gogbashian, Andrew; Ghanta, Ravi K; Umakanthan, Ramanan; Rangaraj, Aravind T; Laurence, Rita G; Fox, John A; Cohn, Lawrence H; Chen, Frederick Y

    2007-09-01

    Less invasive, valve-sparing options are needed for patients with aortic insufficiency (AI). We sought to evaluate the feasibility of reducing AI with an external adjustable aortic ring in an ovine model. To create AI, five sheep underwent patch plasty enlargement of the aortic annulus and root by placement of a 10 x 15 mm pericardial patch between the right and noncoronary cusps. An adjustable external ring composed of a nylon band was fabricated and placed around the aortic root. Aortic flow, aortic pressure, and left ventricular pressures were measured with the ring loose (off) and tightened (on). Mean regurgitant orifice area decreased by 86%, from 0.07 +/- 0.03 cm2 (ring loose, off) to 0.01 +/- 0.00 cm2 (ring tightened, on) [p < 0.01]. The regurgitant fraction decreased from 18 +/- 4% to 2 +/- 1% [p < 0.01]. The ring did not significantly affect stroke volume and aortic pressure. An ovine model of aortic root dilatation resulting in acute AI has been developed. In this model, application of an external, adjustable constricting aortic ring eliminated AI. An aortic ring may be a useful adjunct in reducing AI secondary to annular dilatation.

  12. The use of transcatheter aortic valve replacement vs surgical aortic valve replacement for the treatment of aortic stenosis

    Directory of Open Access Journals (Sweden)

    Jensen HA

    2015-08-01

    Full Text Available Hanna A Jensen, Lillian L Tsai, Vinod H Thourani Division of Cardiothoracic Surgery, Joseph B Whitehead Department of Surgery, Structural Heart and Valve Center, Emory University School of Medicine, Atlanta, GA, USA Abstract: Severe aortic stenosis (AS is associated with considerable morbidity and mortality and is increasing in prevalence as the global population increases. Since AS primarily affects the elderly, many of these patients have comorbidities that make them poor candidates for the gold standard treatment for AS, surgical aortic valve replacement. Transcatheter aortic valve replacement has emerged as a novel technology for the management of AS in higher risk patients over the past decade. Randomized trials have established the safety and efficacy of transcatheter aortic valve replacement, and the medical community has rallied to identify the patients who are most suitable for this transformative treatment. This review focuses on outlining the key procedural differences, describing the unique challenges of both operations, and finally assessing and comparing outcomes both on a general level and in challenging patient subgroups. Keywords: aortic valve replacement, transcatheter aortic valve replacement, surgical aortic valve replacement 

  13. Aortic root surgery in Marfan syndrome: Comparison of aortic valve-sparing reimplantation versus composite grafting.

    Science.gov (United States)

    Karck, Matthias; Kallenbach, Klaus; Hagl, Christian; Rhein, Christine; Leyh, Rainer; Haverich, Axel

    2004-02-01

    The objective of this study was to compare the results of aortic valve-sparing reimplantation and aortic root replacement with mechanical valve conduits in patients with Marfan syndrome undergoing operation for aortic root aneurysms. Patients and methods Between March 1979 and April 2002, 119 patients with clinical evidence of Marfan syndrome underwent composite graft replacement with mechanical valve conduits (n = 74) or aortic valve-sparing reimplantation according to David (n = 45). The underlying causes were aortic dissection type A (43 patients) and aneurysms (76 patients). Patients undergoing aortic valve reimplantation were younger compared with patients undergoing composite grafting (28 vs 35 years, P =.002) and had longer intraoperative aortic crossclamp times (125 vs 78 minutes, P valve reimplantation (P =.15). Mean follow-up was 30 months for patients undergoing aortic valve reimplantation and 114 months for patients undergoing composite grafting. Freedom from reoperation and death after 5 years postoperatively was 92% and 89% in patients undergoing composite grafting and 84% and 96% in patients undergoing aortic valve reimplantation (P =.31; P =.54), respectively. Thromboembolic complications or late postoperative bleeding occurred in 17 patients undergoing composite grafting, and an early postoperative event occurred in 1 patient undergoing aortic valve reimplantation. The results of aortic valve reimplantation and composite grafting of the aortic valve and ascending aorta with mechanical valve conduits are similar with regard to early and mid-term postoperative mortality and to the incidence of late reoperations in patients with Marfan syndrome. The low risk of thromboembolic or bleeding complications favors aortic valve reimplantation in these patients.

  14. The stable stiffness triangle - drained sand during deformation cycles

    DEFF Research Database (Denmark)

    Sabaliauskas, Tomas; Ibsen, Lars Bo

    2017-01-01

    Cyclic, drained sand stiffness was observed using the Danish triaxial appa- ratus. New, deformation dependant soil property (the stable stiffness triangle) was detected. Using the the stable stiffness triangle, secant stiffness of drained sand was plausible to predict (and control) even during ir...... findings can find application in off-shore, seismic and other engi- neering practice, or inspire new branches of research and modelling wherever dynamic, cyclic or transient loaded sand is encountered....

  15. A Rapid Aeroelasticity Optimization Method Based on the Stiffness characteristics

    OpenAIRE

    Yuan, Zhe; Huo, Shihui; Ren, Jianting

    2018-01-01

    A rapid aeroelasticity optimization method based on the stiffness characteristics was proposed in the present study. Large time expense in static aeroelasticity analysis based on traditional time domain aeroelasticity method is solved. Elastic axis location and torsional stiffness are discussed firstly. Both torsional stiffness and the distance between stiffness center and aerodynamic center have a direct impact on divergent velocity. The divergent velocity can be adjusted by changing the cor...

  16. Electromagnetic properties of proximity systems

    Science.gov (United States)

    Kresin, Vladimir Z.

    1985-07-01

    Magnetic screening in the proximity system Sα-Mβ, where Mβ is a normal metal N, semiconductor (semimetal), or a superconductor, is studied. Main attention is paid to the low-temperature region where nonlocality plays an important role. The thermodynamic Green's-function method is employed in order to describe the behavior of the proximity system in an external field. The temperature and thickness dependences of the penetration depth λ are obtained. The dependence λ(T) differs in a striking way from the dependence in usual superconductors. The strong-coupling effect is taken into account. A special case of screening in a superconducting film backed by a size-quantizing semimetal film is considered. The results obtained are in good agreement with experimental data.

  17. Electromagnetic properties of proximity systems

    International Nuclear Information System (INIS)

    Kresin, V.Z.

    1985-01-01

    Magnetic screening in the proximity system S/sub α/-M/sub β/, where M/sub β/ is a normal metal N, semiconductor (semimetal), or a superconductor, is studied. Main attention is paid to the low-temperature region where nonlocality plays an important role. The thermodynamic Green's-function method is employed in order to describe the behavior of the proximity system in an external field. The temperature and thickness dependences of the penetration depth lambda are obtained. The dependence lambda(T) differs in a striking way from the dependence in usual superconductors. The strong-coupling effect is taken into account. A special case of screening in a superconducting film backed by a size-quantizing semimetal film is considered. The results obtained are in good agreement with experimental data

  18. Decreasing Compensatory Ability of Concentric Ventricular Hypertrophy in Aortic-Banded Rat Hearts

    Directory of Open Access Journals (Sweden)

    Alexandre Lewalle

    2018-02-01

    Full Text Available The cardiac system compensates for variations in physiological and pathophysiological conditions through a dynamic remodeling at the organ, tissue, and intracellular levels in order to maintain function. However, on longer time scales following the onset of ventricular pressure overload, such remodeling may begin to inhibit physiological function and ultimately lead to heart failure. This progression from compensatory to decompensatory behavior is poorly understood, in particular owing to the absence of a unified perspective of the concomitantly remodeling subsystems. To address this issue, the present study investigates the evolution of compensatory mechanisms, in response to overload, by integrating diffusion-tensor MRI, echocardiography, and intracellular and hemodynamic measurements within consistent computational simulations of aortic-banded rat hearts. This approach allows a comparison of the relative leverage of different cardiac properties (geometry, passive mechanical stiffness, fiber configuration, diastolic and peak calcium concentrations, calcium-binding affinity, and aortic impedance to affect cardiac contraction. Measurements indicate that, following aortic banding, an ejection fraction (EF of 75% was maintained, relative to control rats, despite significant remodeling of the left-ventricular wall thickness (increasing by ~90% over 4 weeks. Applying our framework, we identified the left-ventricular wall thickness (concentric hypertrophy and the intracellular calcium dynamics as playing the dominant roles in preserving EF acutely, whereas the significance of hypertrophy decreased subsequently. This trend suggests an increasing reliance on intracellular mechanisms (average increase ~50%, rather than on anatomical features (average decrease ~60%, to achieve compensation of pump function in the early phase of heart failure.

  19. Effect of vitamin D on aortic remodeling in streptozotocin-induced diabetes

    Directory of Open Access Journals (Sweden)

    Salum Erik

    2012-07-01

    diabetic rats and improved by vitamin D supplementation. Conclusion PWV profile determined under isobaric conditions demonstrated differential effects of uncontrolled diabetes on aortic stiffness. Diabetes was also associated with elevated serum levels of ADMA. Vitamin D supplementation did not improve the functional indices of aortic stiffness or endothelial function, but prevented the fragmentation of elastic fibers in the aortic media.

  20. Proximity effect at Millikelvin temperatures

    International Nuclear Information System (INIS)

    Mota, A.C.

    1986-01-01

    Proximity effects have been studied extensively for the past 25 years. Typically, they are in films several thousand angstroms thick at temperatures not so far below T/sub CNS/, the transition temperature of the NS system. Interesting is, however, the proximity effect at temperatures much lower than T/sub CNS/. In this case, the Cooper-pair amplitudes are not small and very long pair penetration lengths into the normal metal can be expected. Thus, we have observed pair penetration lengths. For these investigations very suitable specimens are commercial wires of one filament of NbTi or Nb embedded in a copper matrix. The reasons are the high transmission coefficient at the interface between the copper and the superconductor and the fact that the copper in these commercial wires is rather clean with electron free paths between 5 to 10 μm long. In this paper, the magnetic properties of thick proximity systems in the range of temperatures between T/sub CNS/ and 5 x 10/sup -4/ T/sub CNS/ in both low and high magnetic fields are discussed

  1. Circulating Anti-Elastin Antibody Levels and Arterial Disease Characteristics: Associations with Arterial Stiffness and Atherosclerosis.

    Science.gov (United States)

    Lee, Seung-Hyun; Shin, Kihyuk; Park, Sungha; Kang, Seok-Min; Choi, Donghoon; Lee, Seung-Hyo; Lee, Sang-Hak

    2015-11-01

    Elastin is a major arterial structural protein, and elastin-derived peptides are related to arterial change. We previously reported on a novel assay developed using aortic elastin peptides; however, its clinical implications remain unclear. In this study, we assessed whether anti-elastin antibody titers reflect the risk of coronary artery disease (CAD) or its characteristics. We included 174 CAD patients and 171 age- and sex-matched controls. Anti-elastin antibody titers were quantified by enzyme-linked immunosorbent assay. Parameters of arterial stiffness, including the augmentation index (AI) and heart-to-femoral pulse wave velocity (hfPWV), were measured non-invasively. The clinical and angiographic characteristics of CAD patients were also evaluated. Associations between anti-elastin levels and vascular characteristics were examined by linear regression analysis. The median blood level of anti-elastin was significantly lower in the CAD group than in the controls [197 arbitrary unit (a.u.) vs. 63 a.u., pelastin were significantly lower in men and in subjects with hypertension, diabetes mellitus, hyperlipidemia, or high hfPWV. Nevertheless, anti-elastin levels were not dependent on atherothrombotic events or the angiographic severity of CAD. In a multivariate analysis, male sex (β=-0.38, pelastin levels. Lower levels of anti-elastin are related to CAD. The association between antibody titers and CAD is linked to arterial stiffness rather than the advancement of atherosclerosis.

  2. A novel energy-efficient rotational variable stiffness actuator

    NARCIS (Netherlands)

    Rao, S.; Carloni, Raffaella; Stramigioli, Stefano

    This paper presents the working principle, the design and realization of a novel rotational variable stiffness actuator, whose stiffness can be varied independently of its output angular position. This actuator is energy-efficient, meaning that the stiffness of the actuator can be varied by keeping

  3. Direct measurement of the intrinsic ankle stiffness during standing

    NARCIS (Netherlands)

    Vlutters, Mark; Vlutters, M.; Boonstra, Tjitske; Schouten, Alfred Christiaan; van der Kooij, Herman

    2015-01-01

    Ankle stiffness contributes to standing balance, counteracting the destabilizing effect of gravity. The ankle stiffness together with the compliance between the foot and the support surface make up the ankle-foot stiffness, which is relevant to quiet standing. The contribution of the intrinsic

  4. Factors Affecting Optimal Aortic Remodeling After Thoracic Endovascular Aortic Repair of Type B (IIIb) Aortic Dissection

    International Nuclear Information System (INIS)

    Chen, I-Ming; Chen, Po-Lin; Huang, Chun-Yang; Weng, Shih-Hsien; Chen, Wei-Yuan; Shih, Chun-Che

    2017-01-01

    PurposeThe purpose of this study was to determine factors associated with entire aortic remodeling after thoracic endovascular aortic repair (TEVAR) in patients with type B dissection.Materials and MethodsThe patients with type B (IIIb) dissections who underwent TEVAR from 2006 to 2013 with minimum of 2 years of follow-up computed tomography data were retrospectively reviewed. Based on the status of false lumen remodeling of entire aorta, patients were divided into three groups: complete regression, total thrombosis, and inadequate regression with patent abdominal false lumen.ResultsA total of 90 patients (72 males, 18 females; mean age 56.6 ± 16.4 years) were included and divided into the complete regression (n = 22), total thrombosis (n = 18), and inadequate regression (n = 50) groups. Multivariate logistic regression analysis indicated that dissection extension to iliac arteries, increased preoperative number of dissection tear over abdominal aorta, and decreased preoperative abdominal aorta bifurcation true lumen ratio, as compared between the inadequate and complete regression groups, were associated with a persistent false lumen (odds ratio = 33.33, 2.304, and 0.021; all, p ≤ 0.012). Comparison of 6, 12, and 24 months postoperative data revealed no significant differences at any level, suggesting that the true lumen area ratio might not change after 6 months postoperatively.ConclusionsIncreased preoperative numbers of dissection tear around the abdominal visceral branches, dissection extension to the iliac arteries, and decreased preoperative true lumen area ratio of abdominal aorta are predictive of entire aortic remodeling after TEVAR in patients with type B dissection.Level of EvidenceIII.

  5. Factors Affecting Optimal Aortic Remodeling After Thoracic Endovascular Aortic Repair of Type B (IIIb) Aortic Dissection

    Energy Technology Data Exchange (ETDEWEB)

    Chen, I-Ming [National Yang Ming University, Institute of Clinical Medicine, School of Medicine (China); Chen, Po-Lin; Huang, Chun-Yang [National Yang Ming University, Department of Medicine, School of Medicine (China); Weng, Shih-Hsien; Chen, Wei-Yuan; Shih, Chun-Che, E-mail: ccshih@vghtpe.gov.tw [National Yang Ming University, Institute of Clinical Medicine, School of Medicine (China)

    2017-05-15

    PurposeThe purpose of this study was to determine factors associated with entire aortic remodeling after thoracic endovascular aortic repair (TEVAR) in patients with type B dissection.Materials and MethodsThe patients with type B (IIIb) dissections who underwent TEVAR from 2006 to 2013 with minimum of 2 years of follow-up computed tomography data were retrospectively reviewed. Based on the status of false lumen remodeling of entire aorta, patients were divided into three groups: complete regression, total thrombosis, and inadequate regression with patent abdominal false lumen.ResultsA total of 90 patients (72 males, 18 females; mean age 56.6 ± 16.4 years) were included and divided into the complete regression (n = 22), total thrombosis (n = 18), and inadequate regression (n = 50) groups. Multivariate logistic regression analysis indicated that dissection extension to iliac arteries, increased preoperative number of dissection tear over abdominal aorta, and decreased preoperative abdominal aorta bifurcation true lumen ratio, as compared between the inadequate and complete regression groups, were associated with a persistent false lumen (odds ratio = 33.33, 2.304, and 0.021; all, p ≤ 0.012). Comparison of 6, 12, and 24 months postoperative data revealed no significant differences at any level, suggesting that the true lumen area ratio might not change after 6 months postoperatively.ConclusionsIncreased preoperative numbers of dissection tear around the abdominal visceral branches, dissection extension to the iliac arteries, and decreased preoperative true lumen area ratio of abdominal aorta are predictive of entire aortic remodeling after TEVAR in patients with type B dissection.Level of EvidenceIII.

  6. Impaired sodium-dependent adaptation of arterial stiffness in formerly preeclamptic women: the RETAP-vascular study.

    Science.gov (United States)

    van der Graaf, Anne Marijn; Paauw, Nina D; Toering, Tsjitske J; Feelisch, Martin; Faas, Marijke M; Sutton, Thomas R; Minnion, Magdalena; Lefrandt, Joop D; Scherjon, Sicco A; Franx, Arie; Navis, Gerjan; Lely, A Titia

    2016-06-01

    Women with a history of preeclampsia have an increased risk for cardiovascular diseases later in life. Persistent vascular alterations in the postpartum period might contribute to this increased risk. The current study assessed arterial stiffness under low sodium (LS) and high sodium (HS) conditions in a well-characterized group of formerly early-onset preeclamptic (fPE) women and formerly pregnant (fHP) women. Eighteen fHP and 18 fPE women were studied at an average of 5 yr after pregnancy on 1 wk of LS (50 mmol Na(+)/day) and 1 wk of HS (200 mmol Na(+)/day) intake. Arterial stiffness was measured by pulse-wave analysis (aortic augmentation index, AIx) and carotid-femoral pulse-wave velocity (PWV). Circulating markers of the renin-angiotensin aldosterone system (RAAS), extracellular volume (ECV), nitric oxide (NO), and hydrogen sulfide (H2S) were measured in an effort to identify potential mechanistic elements underlying adaptation of arterial stiffness. AIx was significantly lower in fHP women on LS compared with HS while no difference in AIx was apparent in fPE women. PWV remained unchanged upon different sodium loads in either group. Comparable sodium-dependent changes in RAAS, ECV, and NO/H2S were observed in fHP and fPE women. fPE women have an impaired ability to adapt their arterial stiffness in response to changes in sodium intake, independently of blood pressure, RAAS, ECV, and NO/H2S status. The pathways involved in impaired adaptation of arterial stiffness, and its possible contribution to the increased long-term risk for cardiovascular diseases in fPE women, remain to be investigated. Copyright © 2016 the American Physiological Society.

  7. Aortography following subdiaphragmal aortic biopsy

    International Nuclear Information System (INIS)

    Schimmler, J.

    1982-01-01

    A juxtaposition of the subdiaphragmal and infrarenal translumbar aortic biopsy sites showed decisive advantages in favour of the higher site: a more stable position because of better anatomic fixation and rarer incidence of vascular alterations, a wider vascular lumen. Disadvantages lie in the fact that the large visceral arteries (especially Tr. coeliacus) branch off nearly and in the close anatomic relationship to large abdominal organs and the thoracal region. Evaluation of the radiographical image of the vascular tree after subdiaphragmal aortic biopsy showed an average 82% of the vessels to the area of the Knees to be assessable (renal arteries approximately 93%, popliteal arteries approximately 70%). Beyong, the method proved unsatisfactory: 52% of the vessels could not, or not safety, be evaluated. A relatively broad spectrum of indications by comparison with transfemoral catheter aortography had no influence on the rate of complications with reference to either method. A comparison of the topographic conditions shows the need for even more scrupulons observation of the technique in subdiaphragmal biopsy than in the infrarenal one. To sum up the results obtained, subdiaphregmal translumbar aortography is to be preferred to the infrarenal one where transfemoral catheter aortography is contra-indicated, within the limits mentioned. (orig.) [de

  8. Imaging of thoracic aortic dissection

    International Nuclear Information System (INIS)

    Vu, F.H.; Young, N.; Soo, Y.S.

    1994-01-01

    Acute thoracic aortic dissection has a high mortality rate if untreated, so the diagnosis must be rapidly made. Multiple imaging techniques are often used. This retrospective study from 1988 to 1993 assesses the usefulness in diagnosis of chest X-rays, computed tomography (CT) scanning, aortography, magnetic resonance imaging (MRI), trans-thoracic (TTE) and trans-oesophageal (TOE) echocardiography. Forty-two patients with a final clinical diagnosis of dissection were studied. The diagnosis was confirmed in 16 (13 at surgery and three at autopsy). Three died with dissection given as the only cause of death. Chest X-ray abnormalities were seen in all 19 patients with surgery or death from dissection, with a widened mediastinum and/or dilated aorta being present in 17. In the group of 16 patients with surgery or autopsy proof, CT scans found dissections in 9 out of 12 patients studied and correctly classified the type in only five. Aortography was preformed in five, with accurate depiction of dissection and type in all. TTE found dissections in three of eight patients imaged by this method. MRI and TOE were preformed each on two patients, with accurate depiction of dissection and type in each. Because of the relatively low sensitivity of CT scanning in defining aortic dissections Westmead Hospital is currently assessing the use of TOE as the prime imaging modality prior to surgical intervention. 17 refs., 4 tabs., 4 figs

  9. Ascending aortic injuries following blunt trauma.

    Science.gov (United States)

    Sun, Xiumei; Hong, Jenny; Lowery, Robert; Goldstein, Steven; Wang, Zuyue; Lindsay, Joseph; Hill, Peter C; Corso, Paul J

    2013-11-01

    The diagnosis and the management of traumatic thoracic aortic injuries have undergone significant changes due to new technology and improved prehospital care. Most of the discussions have focused on descending aortic injuries. In this review, we discuss the recent management of ascending aortic injuries. We found 5 cohort studies on traumatic aortic injuries and 11 case reports describing ascending aortic injuries between 1998 to the present through Medline research. Among case reports, 78.9% of cases were caused by motor vehicle accidents (MVA). 42.1% of patients underwent emergent open repair and the operative mortality was 12.5%. 36.8% underwent delayed repair. Associated injuries occurred in 84.2% of patients. Aortic valve injury was concurrent in 26.3% of patients. The incidence of ascending aortic injury ranged 1.9-20% in cohort studies. Traumatic injuries to the ascending aorta are relatively uncommon among survivors following blunt trauma. Aortography has been replaced by computed tomography and echocardiography as a diagnostic tool. Open repair, either emergent or delayed, remains the treatment of choice. © 2013 Wiley Periodicals, Inc.

  10. Aortic stenosis and vascular calcifications in alkaptonuria.

    Science.gov (United States)

    Hannoush, Hwaida; Introne, Wendy J; Chen, Marcus Y; Lee, Sook-Jin; O'Brien, Kevin; Suwannarat, Pim; Kayser, Michael A; Gahl, William A; Sachdev, Vandana

    2012-02-01

    Alkaptonuria is a rare metabolic disorder of tyrosine catabolism in which homogentisic acid (HGA) accumulates and is deposited throughout the spine, large joints, cardiovascular system, and various tissues throughout the body. In the cardiovascular system, pigment deposition has been described in the heart valves, endocardium, pericardium, aortic intima and coronary arteries. The prevalence of cardiovascular disease in patients with alkaptonuria varies in previous reports. We present a series of 76 consecutive adult patients with alkaptonuria who underwent transthoracic echocardiography between 2000 and 2009. A subgroup of 40 patients enrolled in a treatment study underwent non-contrast CT scans and these were assessed for vascular calcifications. Six of the 76 patients had aortic valve replacement. In the remaining 70 patients, 12 patients had aortic sclerosis and 7 patients had aortic stenosis. Unlike degenerative aortic valve disease, we found no correlation with standard cardiac risk factors. There was a modest association between the severity of aortic valve disease and joint involvement, however, we saw no correlation with urine HGA levels. Vascular calcifications were seen in the coronaries, cardiac valves, aortic root, descending aorta and iliac arteries. These findings suggest an important role for echocardiographic screening of alkaptonuria patients to detect valvular heart disease and cardiac CT to detect coronary artery calcifications. Published by Elsevier Inc.

  11. Aortic reconstruction with bovine pericardial grafts

    Directory of Open Access Journals (Sweden)

    Silveira Lindemberg Mota

    2003-01-01

    Full Text Available INTRODUCTION: Glutaraldehyde-treated crimped bovine pericardial grafts are currently used in aortic graft surgery. These conduits have become good options for these operations, available in different sizes and shapes and at a low cost. OBJECTIVE:To evaluate the results obtained with bovine pericardial grafts for aortic reconstruction, specially concerning late complications. METHOD: Between January 1995 and January 2002, 57 patients underwent different types of aortic reconstruction operations using bovine pericardial grafts. A total of 29 (50.8% were operated on an urgent basis (mostly acute Stanford A dissection and 28 electively. Thoracotomy was performed in three patients for descending aortic replacement (two patients and aortoplasty with a patch in one. All remaining 54 underwent sternotomy, cardiopulmonary bypass and aortic resection. Deep hypothermia and total circulatory arrest was used in acute dissections and arch operations. RESULTS: Hospital mortality was 17.5%. Follow-up was 24.09 months (18.5 to 29.8 months confidence interval and complication-free actuarial survival curve was 92.3% (standard deviation ± 10.6. Two patients lately developed thoracoabdominal aneurysms following previous DeBakey II dissection and one died from endocarditis. One "patch" aortoplasty patient developed local descending aortic pseudoaneurysm 42 months after surgery. All other patients are asymptomatic and currently clinically evaluated with echocardiography and CT scans, showing no complications. CONCLUSION: Use of bovine pericardial grafts in aortic reconstruction surgery is adequate and safe, with few complications related to the conduits.

  12. The Stress and Stiffness Analysis of Diaphragm

    Directory of Open Access Journals (Sweden)

    Qu Dongyue

    2017-01-01

    Full Text Available Diaphragm coupling with its simple structure, small size, high reliability, which can compensate for its input and output displacement deviation by its elastic deformation, is widely used in aerospace, marine, and chemical etc. This paper uses the ANSYS software and its APDL language to analysis the stress distribution when the diaphragm under the load of torque, axial deviation, centrifugal force, angular deviation and multiple loads. We find that the value of maximum stress usually appears in the outer or inner transition region and the axial deviation has a greater influence to the distribution of the stress. Based on above, we got three kinds of stiffness for axial, angular and torque, which the stiffness of diaphragm is nearly invariable. The results can be regard as an important reference for design and optimization of diaphragm coupling.

  13. Electrothermally Actuated Microbeams With Varying Stiffness

    KAUST Repository

    Tella, Sherif Adekunle

    2017-11-03

    We present axially loaded clamped-guided microbeams that can be used as resonators and actuators of variable stiffness, actuation, and anchor conditions. The applied axial load is implemented by U-shaped electrothermal actuators stacked at one of the beams edges. These can be configured and wired in various ways, which serve as mechanical stiffness elements that control the operating resonance frequency of the structures and their static displacement. The experimental results have shown considerable increase in the resonance frequency and mid-point deflection of the microbeam upon changing the end conditions of the beam. These results can be promising for applications requiring large deflection and high frequency tunability, such as filters, memory devices, and switches. The experimental results are compared to multi-physics finite-element simulations showing good agreement among them.

  14. On the elastic stiffness of grain boundaries

    International Nuclear Information System (INIS)

    Zhang Tongyi; Hack, J.E.

    1992-01-01

    The elastic softening of grain boundaries is evaluated from the starting point of grain boundary energy. Several examples are given to illustrate the relationship between boundary energy and the extent of softening. In general, a high grain boundary energy is associated with a large excess atomic volume in the boundary region. The consequent reduction in grain boundary stiffness can represent a significant fraction of that observed in bulk crystals. (orig.)

  15. Arthrodiastasis for stiff hips in young patients

    OpenAIRE

    Cañadell, J.M. (J. M.); Gonzales, F. (F.); Barrios, R.H. (Raúl H.); Amillo, S. (Santiago)

    1993-01-01

    Joint distraction (arthrodiastasis) with a unilateral fixator was used to treat 9 patients with stiffness of the hip which had followed Perthes' disease (3), epiphysiolysis (2), congenital dysplasia (2), tuberculosis (1) and idiopathic chondrolysis (1). Their average age was 14 years, and they all had pain, limp and shortening of the leg. Distraction of 0.5 to 1 cm was maintained for an average of 94 days. The average range of movement subsequently was 65 degrees compared with 20 degrees befo...

  16. Stiff modes in spinvalve simulations with OOMMF

    Energy Technology Data Exchange (ETDEWEB)

    Mitropoulos, Spyridon [Department of Computer and Informatics Engineering, TEI of Eastern Macedonia and Thrace, Kavala (Greece); Tsiantos, Vassilis, E-mail: tsianto@teikav.edu.gr [Department of Electrical Engineering, TEI of Eastern Macedonia and Thrace, Kavala, 65404 Greece (Greece); Ovaliadis, Kyriakos [Department of Electrical Engineering, TEI of Eastern Macedonia and Thrace, Kavala, 65404 Greece (Greece); Kechrakos, Dimitris [Department of Education, ASPETE, Heraklion, Athens (Greece); Donahue, Michael [Applied and Computational Mathematics Division, NIST, Gaithersburg, MD (United States)

    2016-04-01

    Micromagnetic simulations are an important tool for the investigation of magnetic materials. Micromagnetic software uses various techniques to solve differential equations, partial or ordinary, involved in the dynamic simulations. Euler, Runge-Kutta, Adams, and BDF (Backward Differentiation Formulae) are some of the methods used for this purpose. In this paper, spinvalve simulations are investigated. Evidence is presented showing that these systems have stiff modes, and that implicit methods such as BDF are more effective than explicit methods in such cases.

  17. Water retention properties of stiff silt

    Directory of Open Access Journals (Sweden)

    Barbara Likar

    2017-06-01

    Full Text Available Recent research into the behaviour of soils has shown that it is in fact much more complex than can be described by the mechanics of saturated soils. Nowadays the trend of investigations has shifted towards the unsaturated state. Despite the signifiant progress that has been made so far, there are still a lot of unanswered questions related to the behaviour of unsaturated soils. For this reason, in the fild of geotechnics some new concepts are developed, which include the study of soil suction. Most research into soil suction has involved clayey and silty material, whereas up until recently no data have been available about measurements in very stiff preconsolidated sandy silt. Very stiff preconsolidated sandy silt is typical of the Krško Basin, where it is planned that some very important geotechnical structures will be built, so that knowledge about the behaviour of such soils at increased or decreased water content is essential. Several different methods can be used for soil suction measurements. In the paper the results of measurements carried out on very stiff preconsolidated sandy silt in a Bishop - Wesley double-walled triaxial cell are presented and compared with the results of soil suction measurements performed by means of a potentiometer (WP4C. All the measurement results were evaluated taking into account already known results given in the literature, using the three most commonly used mathematical models. Until now a lot of papers dealing with suction measurements in normal consolidated and preconsolidated clay have been published. Measurements on very stiff preconsolidated sandy silt, as presented in this paper were not supported before.

  18. Arterial Stiffness Is Associated with Peripheral Sensory Neuropathy in Diabetes Patients in Ghana

    Directory of Open Access Journals (Sweden)

    Kwame Yeboah

    2018-01-01

    Full Text Available Objective. Peripheral sensory neuropathy (PSN is among microvascular complications of diabetes that make patients prone to ulceration and amputation. Arterial stiffness is a predictor of cardiovascular diseases and microvascular complications associated with diabetes. We investigated the association between PSN and arterial stiffness, measured as aortic pulse wave velocity (PWVao and cardio-ankle vascular index (CAVI. Method. In a case-control design, arterial stiffness was measured in 240 diabetes patients and 110 nondiabetic control. Large-fibre nerve function was assessed by vibration perception threshold (VPT using a neurothesiometer. PSN was defined as the VPT > 97.5th percentile from age- and gender-adjusted models in nondiabetic controls. Results. The overall prevalence of PSN was 16.6% in the entire study participants. Compared to non-PSN participants, PSN patients had higher levels of PWVao (9.5 ± 1.7 versus 8.7 ± 1.2 m/s, p=0.016 and CAVI (8.4 ± 1.3 versus 7.6 ± 1.1, p=0.001. In multiple regression models, VPT was associated with PWVao (β=0.14, p=0.025 and CAVI (β=0.12, p=0.04. PSN patients had increased odds of CAVI (OR = 1.51 (1.02–2.4, p=0.043, but not PWVao (OR = 1.25 (0.91–1.71, p=0.173. Conclusion. PWVao and CAVI were associated with VPT and PSN in diabetes patients in Ghana. Patients having PSN have increased odds of CAVI, independent of other conventional risk factors.

  19. Morning pressor surge, blood pressure variability, and arterial stiffness in essential hypertension.

    Science.gov (United States)

    Pucci, Giacomo; Battista, Francesca; Anastasio, Fabio; Schillaci, Giuseppe

    2017-02-01

    An excess morning blood pressure surge (MBPS) may portend an increased cardiovascular risk, but the mechanisms thereof have been little investigated. The link between MBPS, short-term blood pressure (BP) variability, and arterial stiffness has not been entirely defined. In 602 consecutive untreated hypertensive patients (48 ± 12 years, 61% men, office BP 149/93 ± 17/10 mmHg), we measured carotid-femoral pulse wave velocity (cf-PWV, SphygmoCor) and 24-h ambulatory BP. Using self-reported sleep and wake times, MBPS was defined as sleep-trough (ST-MBPS), prewaking, rising. Short-term BP variability was calculated as weighted 24-h SBP SD and average real variability of 24-h SBP (ARV), that is, average of absolute differences between consecutive SBP readings. ST-MBPS (r = 0.16, P < 0.001) and rising MBPS (r = 0.12, P = 0.003) showed a direct correlation with cf-PWV, whereas prewaking MBPS had no such relation (r = 0.06, P = 0.14). Only ST-MBPS was independently associated with cf-PWV (t = 1.96, P = 0.04) after adjustment for age, sex, height, office mean arterial pressure, heart rate, and renal function. This association was lost after further adjustment for weighted 24-h SBP SD (P = 0.13) or ARV (P = 0.24). ARV was a significant mediator of the relationship between ST-MBPS and cf-PWV (P = 0.003). In untreated hypertension, ST-MBPS has a direct relation with aortic stiffness, which is mediated by an increased ARV. The adverse effects of MBPS may be partly explained by its link with arterial stiffness, mediated by short-term SBP variability.

  20. The stiffness change and the increase in the ultimate capacity for a stiff pile resulting from a cyclic loading

    DEFF Research Database (Denmark)

    Lada, Aleksandra; Ibsen, Lars Bo; Nicolai, Giulio

    In the paper the experimental results of small-scale tests on a stiff monopile are presented to outline the change in stiffness during the cyclic loading and the change in the ultimate pile capacity. The results confirm the increase of stiffness and the increase in bearing capacity resulting from...

  1. Cryotherapy induces an increase in muscle stiffness.

    Science.gov (United States)

    Point, M; Guilhem, G; Hug, F; Nordez, A; Frey, A; Lacourpaille, L

    2018-01-01

    Although cold application (ie, cryotherapy) may be useful to treat sports injuries and to prevent muscle damage, it is unclear whether it has adverse effects on muscle mechanical properties. This study aimed to determine the effect of air-pulsed cryotherapy on muscle stiffness estimated using ultrasound shear wave elastography. Myoelectrical activity, ankle passive torque, shear modulus (an index of stiffness), and muscle temperature of the gastrocnemius medialis were measured before, during an air-pulsed cryotherapy (-30°C) treatment of four sets of 4 minutes with 1-minute recovery in between and during a 40 minutes postcryotherapy period. Muscle temperature significantly decreased after the second set of treatment (10 minutes: 32.3±2.5°C; Pcryotherapy induces an increase in muscle stiffness. This acute change in muscle mechanical properties may lower the amount of stretch that the muscle tissue is able to sustain without subsequent injury. This should be considered when using cryotherapy in athletic practice. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Exchange stiffness of Ca-doped YIG

    Science.gov (United States)

    Avgin, I.; Huber, D. L.

    1994-05-01

    An effective medium theory for the zero-temperature exchange stiffness of uncompensated Ca-doped YIG is presented. The theory is based on the assumption that the effect of the Ca impurities is to produce strong, random ferromagnetic interactions between spins on the a and d sublattices. In the simplest version of the theory, a fraction, x, of the ad exchange integrals are large and positive, x being related to the Ca concentration. The stiffness is calculated as function of x for arbitrary perturbed ad exchange integral, Jxad. For Jxad≳(1/5)‖8Jaa+3Jdd‖, with Jaa and Jdd denoting the aa and dd exchange integrals, respectively, there is a critical concentration, Xc, such that when x≳Xc, the stiffness is complex. It is suggested that Xc delineates the region where there are significant departures from colinearity in the ground state of the Fe spins. Extension of the theory to a model where the Ca doping is assumed to generate Fe4+ ions on the tetrahedral sites is discussed. Possible experimental tests of the theory are mentioned.

  3. Importance of stent-graft design for aortic arch aneurysm repair

    Directory of Open Access Journals (Sweden)

    C Singh

    2017-02-01

    Full Text Available Aneurysm of the aorta is currently treated by open surgical repair or endovascular repair. However, when the aneurysm occurs in regions between the aortic arch and proximal descending aorta, it can be a complex pathology to treat due to its intricate geometry. When complex aortic aneurysms are treated with the conventional procedures, some of the patients present with significant post-operative complications and high mortality rate. Consequently, a clinically driven hybrid innovation known as the frozen elephant trunk procedure was introduced to treat complex aortic aneurysms. Although this procedure significantly reduces mortality rate and operating time, it is still associated with complications such as endoleaks, spinal cord ischemia, renal failure and stroke. Some of these complications are consequences of a mismatch in the biomechanical behaviour of the stent-graft device and the aorta. Research on complex aneurysm repair tended to focus more on the surgical procedure than the stent-graft design. Current stent-graft devices are suitable for straight vessels. However, when used to treat aortic aneurysm with complex geometry, these devices are ineffective in restoring the normal biological and biomechanical function of the aorta. A stent-graft device with mechanical properties that are comparable with the aorta and aortic arch could possibly lead to fewer post-operative complications, thus, better outcome for patients with complex aneurysm conditions. This review highlights the influence stent-graft design has on the biomechanical properties of the aorta which in turn can contribute to complications of complex aneurysm repair. Design attributes critical for minimising postoperative biomechanical mismatch are also discussed.

  4. Altered aortic shape in bicuspid aortic valve relatives influences blood flow patterns.

    Science.gov (United States)

    Schnell, Susanne; Smith, Danielle A; Barker, Alex J; Entezari, Pegah; Honarmand, Amir R; Carr, Maria L; Malaisrie, S Chris; McCarthy, Patrick M; Collins, Jeremy; Carr, James C; Markl, Michael

    2016-11-01

    Bicuspid aortic valve (BAV) is known to exhibit familial inheritance and is associated with aortopathy and altered aortic haemodynamics. However, it remains unclear whether BAV-related aortopathy can be inherited independently of valve morphology. Four-dimensional flow magnetic resonance imaging for the in vivo assessment of thoracic aortic 3D blood flow was performed in 24 BAV relatives with trileaflet aortic valves (age = 40 ± 14 years) and 15 healthy controls (age = 37 ± 10 years). Data analysis included aortic dimensions, shape (round/gothic/cubic), and 3D blood flow characteristics (semi-quantitative vortex/helix grading and peak velocities). Cubic and gothic aortic shapes were markedly more prevalent in BAV relatives compared with controls (38 vs. 7%). Ascending aorta (AAo) vortex flow in BAV relatives was significantly increased compared with controls (grading = 1.5 ± 1.0 vs. 0.6 ± 0.9, P = 0.015). Aortic haemodynamics were influenced by aortic shape: peak velocities were reduced for gothic aortas vs. round aortas (P = 0.003); vortex flow was increased for cubic aortas in the AAo (P gothic aortas in the AAo and descending aorta (P = 0.003, P = 0.029). Logistic regression demonstrated significant associations of shape with severity of vortex flow in AAo (P < 0.001) and aortic arch (P = 0.016) in BAV relatives. BAV relatives expressed altered aortic shape and increased vortex flow despite the absence of valvular disease or aortic dilatation. These data suggest a heritable component of BAV-related aortopathy affecting aortic shape and aberrant blood flow, independent of valve morphology. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

  5. Combined Repair of Ascending Aortic Pseudoaneurysm and Abdominal Aortic Aneurysm in a Patient with Marfan Syndrome

    OpenAIRE

    Kokotsakis, John N.; Lioulias, Achilleas G.; Foroulis, Christophoros N.; Skouteli, Eleni Anna T.; Milonakis, Michael K.; Bastounis, Elias A.; Boulafendis, Dimitrios G.

    2003-01-01

    Pseudoaneurysms of the ascending aorta after the original inclusion/wrap technique of the Bentall procedure present a difficult surgical management problem and are associated with substantial morbidity and mortality. Patients with Marfan syndrome frequently develop aneurysms and dissections that involve multiple aortic segments. We present the case of a Marfan patient who successfully underwent repair of a giant ascending aortic pseudoaneurysm and concomitant repair of an abdominal aortic ane...

  6. The future of aortic surgery in Europe

    DEFF Research Database (Denmark)

    Czerny, Martin; Bachet, Jean; Bavaria, Joseph

    2012-01-01

    the interested reader with an overview of how aortic surgery and (perhaps more accurately) aortic medicine has evolved in Europe, and its present standing; also to provide a glimpse into the future, trying to disseminate the thoughts of a group of people actively involved in the development of aortic medicine......At least every ten years, each specialty should reflect upon its past, its present and its future, in order to be able to reconfirm the direction in which it is headed, to adopt suggestions from inside and outside and, consequently, to improve. As such, the aim of this manuscript is to provide...

  7. Mycotic Aneurysm of the Aortic Arch

    Directory of Open Access Journals (Sweden)

    Ji Hye Seo

    2014-08-01

    Full Text Available A mycotic aneurysm of the thoracic aorta is rare. We report a case of mycotic aneurysm that developed in the aortic arch. An 86-year-old man was admitted with fever and general weakness. Blood culture yielded methicillin-resistant Staphylococcus aureus. Chest X-ray showed an enlarged aortic arch, and computed tomography scan revealed an aneurysm in the aortic arch. The patient was treated only with antibiotics and not surgically. The size of the aneurysm increased rapidly, resulting in bronchial obstruction and superimposed pneumonia. The patient died of respiratory failure.

  8. Static stiffness modeling of a novel hybrid redundant robot machine

    International Nuclear Information System (INIS)

    Li Ming; Wu Huapeng; Handroos, Heikki

    2011-01-01

    This paper presents a modeling method to study the stiffness of a hybrid serial-parallel robot IWR (Intersector Welding Robot) for the assembly of ITER vacuum vessel. The stiffness matrix of the basic element in the robot is evaluated using matrix structural analysis (MSA); the stiffness of the parallel mechanism is investigated by taking account of the deformations of both hydraulic limbs and joints; the stiffness of the whole integrated robot is evaluated by employing the virtual joint method and the principle of virtual work. The obtained stiffness model of the hybrid robot is analytical and the deformation results of the robot workspace under certain external load are presented.

  9. PULSE WAVE VELOCITY AND CENTRAL AORTIC PRESSURE IN OBESE CHILDREN ACCORDING TO THE NON-INVASIVE ARTERIOGRAPHY RESULTS

    Directory of Open Access Journals (Sweden)

    O. V. Kozhevnikova

    2013-01-01

    Full Text Available The article presents information value of non-invasive arteriography, which reveals early signs of cardiovascular pathology formation in children, using a large number of trials in children. The authors examined predictors of cardiovascular catastrophes’ development, confirmed in adults: aortic wall’s stiffness, central aortic pressure and pulse pressure – that have not been sufficiently studied in children yet. The article shows that the high-technology method of non-invasive arteriography allows revealing changes of these parameters in children on the preclinical stage. It also shows their correlation with body mass index, fatty hepatosis, direct correlation of weight gain with connection of pulse wave velocity and central blood pressure and importance of follow-up evaluation of these parameters. Heterogeneity of the group of obese children in terms of these parameters is a premise for development of individual approach to control and prevention of cardiovascular complications’ development risk in childhood.

  10. The role of aortic wall CT attenuation measurements for the diagnosis of acute aortic syndromes

    International Nuclear Information System (INIS)

    Knollmann, Friedrich D.; Lacomis, Joan M.; Ocak, Iclal; Gleason, Thomas

    2013-01-01

    Objectives: To determine if measurements of aortic wall attenuation can improve the CT diagnosis of acute aortic syndromes. Methods: CT reports from a ten year period were searched for acute aortic syndromes (AAS). Studies with both an unenhanced and a contrast enhanced (CTA) series that had resulted in the diagnosis of intramural hematoma (IMH) were reviewed. Diagnoses were confirmed by medical records. The attenuation of aortic wall abnormalities was measured. The observed attenuation threshold was validated using studies from 39 new subjects with a variety of aortic conditions. Results: The term “aortic dissection” was identified in 1206, and IMH in 124 patients’ reports. IMH was confirmed in 31 patients, 21 of whom had both unenhanced and contrast enhanced images. All 21 had pathologic CTA findings, and no CTA with IMH was normal. Attenuation of the aortic wall was greater than 45 HUs on the CTA images in all patients with IMH. When this threshold was applied to the new group, sensitivity for diagnosing AAS was 100% (19/19), and specificity 94% (16/17). Addition of unenhanced images did not improve accuracy. Conclusions: Measurements of aortic wall attenuation in CTA have a high negative predictive value for the diagnosis of acute aortic syndromes

  11. The role of aortic wall CT attenuation measurements for the diagnosis of acute aortic syndromes

    Energy Technology Data Exchange (ETDEWEB)

    Knollmann, Friedrich D., E-mail: friedrich.knollmann@ucdmc.ucdavis.edu [Department of Radiology, University of California, Davis, 4860 Y Street, Sacramento, CA 95817 (United States); Departments of Radiology and Cardiothoracic Surgery, University of Pittsburgh, 200 Lothrop Street, Pittsburgh, PA 15213 (United States); Lacomis, Joan M.; Ocak, Iclal; Gleason, Thomas [Department of Radiology, University of California, Davis, 4860 Y Street, Sacramento, CA 95817 (United States); Departments of Radiology and Cardiothoracic Surgery, University of Pittsburgh, 200 Lothrop Street, Pittsburgh, PA 15213 (United States)

    2013-12-01

    Objectives: To determine if measurements of aortic wall attenuation can improve the CT diagnosis of acute aortic syndromes. Methods: CT reports from a ten year period were searched for acute aortic syndromes (AAS). Studies with both an unenhanced and a contrast enhanced (CTA) series that had resulted in the diagnosis of intramural hematoma (IMH) were reviewed. Diagnoses were confirmed by medical records. The attenuation of aortic wall abnormalities was measured. The observed attenuation threshold was validated using studies from 39 new subjects with a variety of aortic conditions. Results: The term “aortic dissection” was identified in 1206, and IMH in 124 patients’ reports. IMH was confirmed in 31 patients, 21 of whom had both unenhanced and contrast enhanced images. All 21 had pathologic CTA findings, and no CTA with IMH was normal. Attenuation of the aortic wall was greater than 45 HUs on the CTA images in all patients with IMH. When this threshold was applied to the new group, sensitivity for diagnosing AAS was 100% (19/19), and specificity 94% (16/17). Addition of unenhanced images did not improve accuracy. Conclusions: Measurements of aortic wall attenuation in CTA have a high negative predictive value for the diagnosis of acute aortic syndromes.

  12. Aortic root reimplantation procedure: a new milestone in aortic valve-sparing operations

    Directory of Open Access Journals (Sweden)

    А. М. Чернявский

    2016-08-01

    Full Text Available Aim: Emphasis in this study was placed on clinical and functional assessment of a modified "Florida Sleeve" procedure during surgical correction of ascending aorta aneurysms with concomitant aortic insufficiency.Methods: 32 patients with an aneurysm of the ascending aorta and aortic insufficiency underwent a modified "Florida Sleeve" procedure. The average follow-up was 17 (0-60 months. The average age of patients was 57±13 (23-73 years 56±13 years.Results: The expected 4-year cumulative survival rate was 84.3%. Overall freedom from aortic insufficiency in the late period was 88.9%. Median aortic regurgitation was 1+ (1; 2. Long-term follow-up revealed no valve-associated complications.Conclusion: The aortic root reimplantation procedure enables optimal correction of the existing lesions of the aortic root without performing aortic valve replacement and demonstrates stable clinical and functional outcomes in the long-term period.Key words: aortic aneurysm; aortic valve; valve-sparing operations.FundingThe study had no sponsorship.Conflict of interestThe authors declare no conflict of interest.

  13. Lower Body Stiffness Modulation Strategies in Well Trained Female Athletes.

    Science.gov (United States)

    Millett, Emma L; Moresi, Mark P; Watsford, Mark L; Taylor, Paul G; Greene, David A

    2016-10-01

    Millett, EL, Moresi, MP, Watsford, ML, Taylor, PG, and Greene, DA. Lower body stiffness modulation strategies in well trained female athletes. J Strength Cond Res 30(10): 2845-2856, 2016-Lower extremity stiffness quantifies the relationship between the amount of leg compression and the external load to which the limb are subjected. This study aimed to assess differences in leg and joint stiffness and the subsequent kinematic and kinetic control mechanisms between athletes from various training backgrounds. Forty-seven female participants (20 nationally identified netballers, 13 high level endurance athletes and 14 age and gender matched controls) completed a maximal unilateral countermovement jump, drop jump and horizontal jump to assess stiffness. Leg stiffness, joint stiffness and associated mechanical parameters were assessed with a 10 camera motion analysis system and force plate. No significant differences were evident for leg stiffness measures between athletic groups for any of the tasks (p = 0.321-0.849). However, differences in joint stiffness and its contribution to leg stiffness, jump performance outcome measures and stiffness control mechanisms were evident between all groups. Practitioners should consider the appropriateness of the task utilised in leg stiffness screening. Inclusion of mechanistic and/or more sports specific tasks may be more appropriate for athletic groups.

  14. JAG Tearing Technique with Radiofrequency Guide Wire for Aortic Fenestration in Thoracic Endovascular Aneurysm Repair

    International Nuclear Information System (INIS)

    Ricci, Carmelo; Ceccherini, Claudio; Leonini, Sara; Cini, Marco; Vigni, Francesco; Neri, Eugenio; Tucci, Enrico; Benvenuti, Antonio; Tommasino, Giulio; Sassi, Carlo

    2012-01-01

    An innovative approach, the JAG tearing technique, was performed during thoracic endovascular aneurysm repair in a patient with previous surgical replacement of the ascending aorta with a residual uncomplicated type B aortic dissection who developed an aneurysm of the descending thoracic aorta with its lumen divided in two parts by an intimal flap. The proximal landing zone was suitable to place a thoracic stent graft. The distal landing zone was created by cutting the intimal flap in the distal third of the descending thoracic aorta with a radiofrequency guide wire and intravascular ultrasound catheter.

  15. Equilibrium properties of proximity effect

    International Nuclear Information System (INIS)

    Esteve, D.; Pothier, H.; Gueron, S.; Birge, N.O.; Devoret, M.

    1996-01-01

    The proximity effect in diffusive normal-superconducting (NS) nano-structures is described by the Usadel equations for the electron pair correlations. We show that these equations obey a variational principle with a potential which generalizes the Ginzburg-Landau energy functional. We discuss simple examples of NS circuits using this formalism. In order to test the theoretical predictions of the Usadel equations, we have measured the density of states as a function of energy on a long N wire in contact with a S wire at one end, at different distances from the NS interface. (authors)

  16. Equilibrium properties of proximity effect

    Energy Technology Data Exchange (ETDEWEB)

    Esteve, D.; Pothier, H.; Gueron, S.; Birge, N.O.; Devoret, M.

    1996-12-31

    The proximity effect in diffusive normal-superconducting (NS) nano-structures is described by the Usadel equations for the electron pair correlations. We show that these equations obey a variational principle with a potential which generalizes the Ginzburg-Landau energy functional. We discuss simple examples of NS circuits using this formalism. In order to test the theoretical predictions of the Usadel equations, we have measured the density of states as a function of energy on a long N wire in contact with a S wire at one end, at different distances from the NS interface. (authors). 12 refs.

  17. Predictive value of platelet-to-lymphocyte ratio in severe degenerative aortic valve stenosis

    Directory of Open Access Journals (Sweden)

    Efe Edem

    2016-01-01

    Full Text Available Background: Aortic valve stenosis (AVS is the most common cause of left ventricular outflow obstruction, and its prevalence among elderly patients causes a major public health burden. Recently, platelet-to-lymphocyte ratio (PLR has been recognized as a novel prognostic biomarker that offers information about both aggregation and inflammation pathways. Since PLR indicates inflammation, we hypothesized that PLR may be associated with the severity of AVS due to chronic inflammation pathways that cause stiffness and calcification of the aortic valve. Materials and Methods: We retrospectively enrolled 117 patients with severe degenerative AVS, who underwent aortic valve replacement and 117 control patients in our clinic. PLR was defined as the absolute platelet count divided by the absolute lymphocyte count. Severe AVS was defined as calcification and sclerosis of the valve with a mean pressure gradient of >40 mmHg. Results: PLR was 197.03 ± 49.61 in the AVS group and 144.9 ± 40.35 in the control group, which indicated a statistically significant difference (P < 0.001. A receiver operating characteristic (ROC curve analysis demonstrated that PLR values over 188 predicted the severity of aortic stenosis with a sensitivity of 87% and a specificity of 70% (95% confidence interval = 0.734–0.882; P < 0.001; area under ROC curve: 0.808. Conclusion: We suggest that the level of PLR elevation is related to the severity of degenerative AVS, and PLR should be used to monitor patients' inflammatory responses and the efficacy of treatment, which will lead us to more closely monitor this high-risk population to detect severe degenerative AVS at an early stage.

  18. Endovascular aneurysm repair simulation can lead to decreased fluoroscopy time and accurately delineate the proximal seal zone.

    Science.gov (United States)

    Kim, Ann H; Kendrick, Daniel E; Moorehead, Pamela A; Nagavalli, Anil; Miller, Claire P; Liu, Nathaniel T; Wang, John C; Kashyap, Vikram S

    2016-07-01

    The use of simulators for endovascular aneurysm repair (EVAR) is not widespread. We examined whether simulation could improve procedural variables, including operative time and optimizing proximal seal. For the latter, we compared suprarenal vs infrarenal fixation endografts, right femoral vs left femoral main body access, and increasing angulation of the proximal aortic neck. Computed tomography angiography was obtained from 18 patients who underwent EVAR at a single institution. Patient cases were uploaded to the ANGIO Mentor endovascular simulator (Simbionix, Cleveland, Ohio) allowing for three-dimensional reconstruction and adapted for simulation with suprarenal fixation (Endurant II; Medtronic Inc, Minneapolis, Minn) and infrarenal fixation (C3; W. L. Gore & Associates Inc, Newark, Del) deployment systems. Three EVAR novices and three experienced surgeons performed 18 cases from each side with each device in randomized order (n = 72 simulations/participant). The cases were stratified into three groups according to the degree of infrarenal angulation: 0° to 20°, 21° to 40°, and 41° to 66°. Statistical analysis used paired t-test and one-way analysis of variance. Mean fluoroscopy time for participants decreased by 48.6% (P time decreased by 33.8% (P zone coverage in highly angulated aortic necks was significantly decreased. The infrarenal device resulted in mean aortic neck zone coverage of 91.9%, 89.4%, and 75.4% (P zone coverage. The side of femoral access for the main body did not influence proximal seal zone coverage regardless of infrarenal angulation. Simulation of EVAR leads to decreased fluoroscopy times for novice and experienced operators. Side of femoral access did not affect precision of proximal endograft landing. The angulated aortic neck leads to decreased proximal seal zone coverage regardless of infrarenal or suprarenal fixation devices. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  19. Preliminary Evidence for Aortopathy and an X-Linked Parent-of-Origin Effect on Aortic Valve Malformation in a Mouse Model of Turner Syndrome

    Directory of Open Access Journals (Sweden)

    Robert B. Hinton

    2015-07-01

    Full Text Available Turner syndrome (TS, most frequently caused by X-monosomy (45,X, is characterized in part by cardiovascular abnormalities, including aortopathy and bicuspid aortic valve (BAV. There is a need for animal models that recapitulate the cardiovascular manifestations of TS. Extracellular matrix (ECM organization and morphometrics of the aortic valve and proximal aorta were examined in adult 39,XO mice (where the parental origin of the single X was paternal (39,XPO or maternal (39,XMO and 40,XX controls. Aortic valve morphology was normal (tricuspid in all of the 39,XPO and 40,XX mice studied, but abnormal (bicuspid or quadricuspid in 15% of 39,XMO mice. Smooth muscle cell orientation in the ascending aorta was abnormal in all 39,XPO and 39,XMO mice examined, but smooth muscle actin was decreased in 39,XMO mice only. Aortic dilation was present with reduced penetrance in 39,XO mice. The 39,XO mouse demonstrates aortopathy and an X-linked parent-of-origin effect on aortic valve malformation, and the candidate gene FAM9B is polymorphically expressed in control and diseased human aortic valves. The 39,XO mouse model may be valuable for examining the mechanisms underlying the cardiovascular findings in TS, and suggest there are important genetic modifiers on the X chromosome that modulate risk for nonsyndromic BAV and aortopathy.

  20. Dissecting aortic aneurysm in maintenance hemodialysis patients

    Directory of Open Access Journals (Sweden)

    Ounissi M

    2009-01-01

    Full Text Available The dissecting aortic aneurysm (DAA is a rare pathology that may result in fatal outcome. We report follow up of three cases of DAA patients undergoing maintenance hemo-dialysis who were managed conservatively.

  1. Traumatic aortic dissection presenting with respiratory arrest

    Directory of Open Access Journals (Sweden)

    C.C. Meyer

    2015-03-01

    Conclusion: Blunt aortic injury is a major cause of death in blunt chest trauma. Signs and symptoms of this injury are nonspecific and other injuries often take precedence, which makes a relatively difficult diagnosis even more challenging.

  2. Aortic root reoperations after pulmonary autograft implantation

    NARCIS (Netherlands)

    J.A. Bekkers (Jos); L.M.A. Klieverik (Loes Maria Anne); G. Bol-Raap (Goris); J.J.M. Takkenberg (Hanneke); A.J.J.C. Bogers (Ad)

    2010-01-01

    textabstractObjective: To report the results of aortic root reoperations after pulmonary autograft implantation. Methods: All consecutive patients in our prospective Ross research database were selected for analysis, and additional information for patients requiring reoperation was obtained from the

  3. Optimal timing of valve replacement in asymptomatic severe aortic stenosis.

    Science.gov (United States)

    Bilen, Emine; Ipek, Gökürk; Ayhan, Huseyin; Nacar, Alper Bugra; Kasapkara, Haci Ahmet; Sani, Cenk; Basbug, Serdar; Kurt, Mustafa; Bozkurt, Engin

    2014-09-01

    Patients with asymptomatic severe aortic stenosis (AS) constitute a heterogeneous group which includes not only certain cases who are at high risk of sudden death and valve-related heart failure, but also those at low risk for these events. Degenerative AS, which includes a majority of patients with AS, is characterized by stricture of the valve, increased arterial stiffness, and diverse left ventricular response to the valvular plus arterial vascular load. In addition to using traditional primary parameters, the severity of AS and the total left ventricular load should be assessed using new measures such as energy loss index and valvulo-arterial impedance. Natriuretic peptide levels and global longitudinal strain imaging may also be used as secondary parameters to obtain information about left ventricular systolic function, although these parameters do not correlate with the severity of AS. Exercise stress testing and exercise echocardiography are also beneficial when assessing the patient if they are symptomatic, and for determining valvular and left ventricular contractile reserves. The aim of this review was to emphasize the importance of risk stratifications in asymptomatic severe AS cases, and to assess the severity of AS using not only conventional methods but also new methods on which much emphasis has been placed during recent years.

  4. [Aortic valve-sparing root reconstruction in Marfan syndrome].

    Science.gov (United States)

    Ogino, H; Sasaki, H; Hanafusa, Y; Hirata, M; Numata, S; Ando, M; Yagihara, T; Kitamura, S

    2002-07-01

    The outcome of aortic valve-sparing root reconstruction in Marfan syndrome was reviewed. Thirteen patients with Marfan syndrome underwent aortic valve-sparing root reconstruction for annuloaortic ectasia or aortic root dissection between 1994 and 1999. The grade of preoperative aortic regurgitation was I in 4, II in 2, III in 5, IV in 2 patients. The procedures of aortic valve-sparing were reimplantation in 7 and remodeling in 5 patients. There was no hospital and late death. Recurrence of aortic regurgitation greater than moderate grade developed in 1 patient immediately after the surgery and in the other 4 patients in the late stage. One patient of them required aortic valve replacement for it. Aortic valve-sparing root reconstruction is applicable in Marfan patients, although the indication should be cautious. Close observation is needed for recurrence of aortic regurgitation.

  5. VCODE, Ordinary Differential Equation Solver for Stiff and Non-Stiff Problems

    International Nuclear Information System (INIS)

    Cohen, Scott D.; Hindmarsh, Alan C.

    2001-01-01

    1 - Description of program or function: CVODE is a package written in ANSI standard C for solving initial value problems for ordinary differential equations. It solves both stiff and non stiff systems. In the stiff case, it includes a variety of options for treating the Jacobian of the system, including dense and band matrix solvers, and a preconditioned Krylov (iterative) solver. 2 - Method of solution: Integration is by Adams or BDF (Backward Differentiation Formula) methods, at user option. Corrector iteration is by functional iteration or Newton iteration. For the solution of linear systems within Newton iteration, users can select a dense solver, a band solver, a diagonal approximation, or a preconditioned Generalized Minimal Residual (GMRES) solver. In the dense and band cases, the user can supply a Jacobian approximation or let CVODE generate it internally. In the GMRES case, the pre-conditioner is user-supplied

  6. CT diagnosis of acute aortic dissection

    International Nuclear Information System (INIS)

    Ogawa, Noriko; Kobayashi, Takeshi

    1989-01-01

    Sixteen (47.5%) of 35 patients with acute aortic dissection showed a non-opacified crescent in the aorta on an initial contrast CT. Seven of these 16 patients underwent cineangiography soon after the initial CT, and in all 7 patients, neither an intimal tear nor an intimal flap was obtained. All but one of above 16 patients were followed by CT. Mean duration of follow-up was 9.6 months. In 10 of 15 patients with non-opacified false lumen, the false lumen remained non-opacified until the last examination. Moreover, in 6 of these 10 patients, the false lumen shrunk, and in the other 3, it disappeared completely on follow-up CT. On the other hand, in remaining 5 of these 15 patients who were initially diagnosed to have non-opacified false lumen, the false lumen became opacified and enlarged in size on follow-up CT performed in the first 14 weeks. Moreover, in 4 of these 5 patients, the false lumen became opacified in the only first 6 weeks. No matter how intensive care should be paid at least for the first 6 weeks, it seems that patients with aortic dissection which have non-opacified false lumen had good prognosis in comparison to patients with ordinary aortic dissections which have opacified false lumen. We believe aortic dissection with non-opacified false lumen may consist of two type of aortic dissection, one has no intimal tear, the other has some intimal tears and a thrombosed false lumen. In conclusion, CT is the most useful modality in diagnosing acute aortic dissection. The reasons are the incidence of acute aortic dissection with non-opacified false lumen was high, patients with non-opacified false lumen had good prognosis, and it was difficult to diagnose aortic dissection with non-opacified false lumen by conventional cineangiography and/or DSA. (author)

  7. Graft infections after surgical aortic reconstructions

    OpenAIRE

    Berger, P.

    2015-01-01

    Prosthetic vascular grafts are frequently used to reconstruct (part) of the aorta. Every surgical procedure caries a certain risk for infection and when a prosthetic aortic graft is implanted, this may lead to an aortic graft infection (AGI). Endovascular techniques have gradually replaced open surgical reconstructions as first line of treatment for aorto-iliac diseases. Nowadays, open reconstructions are primarily reserved for patients unsuitable for endovascular reconstructions or for redo ...

  8. Aortic dissection. Basic aspects and endovascular management

    International Nuclear Information System (INIS)

    Jaramillo, Nicolas I; Alviar, Carlos I

    2005-01-01

    Treatment of thoracic aortic pathology is complicated by the morbidity associated to the surgical procedure and to the frailty of an elderly and difficult population. Surgical operation in this kind of population frequently bears a significant incidence of death and long-term disability. In an effort to reduce the incidence of negative outcomes, minimally invasive techniques in the form of endovascular stenting have been introduced during the past decade. The technology, originally described by Parodi, and initially designed for its use in abdominal aortic aneurysms, has been adapted for the treatment of thoracic aortic aneurysms. Furthermore, an improved understanding of the pathophysiology and the natural history of thoracic aortic disease as well as the analysis of the outcomes have facilitated our treatment decisions in terms of the timing for an appropriate intervention. Treatment of thoracic aortic dissection using endovascular Stent is one of the more recent advances in this condition and is receiving increasing attention, as it is a less invasive alternative to an open surgical repair. Although this technology is still innovative, significant improvements have been made lately in the design and deployment of the endovascular Stent-grafts. These prostheses have been increasingly used to treat aneurysms, dissections and traumatic ruptures, as well as giant penetrating ulcers and intramural hematomas of the descending thoracic aorta with good early and mid-term outcomes. The rareness, complexity and severity of the pathology and the theoretically high risk of complications should render the surgeon extremely cautious especially with young patients. Conceptually, the endo luminal treatment in the acute phase seems to be the solution and will probably become a preferred therapy while technical refinement is under way. Worldwide experience is growing and with this a better understanding of the indications and limitations of this innovative therapy will be

  9. The impact of intervention strategies that target arterial stiffness in end-stage renal disease: a systematic review protocol.

    Science.gov (United States)

    Rodriguez, Rosendo A; Shea, Beverley; Hae, Richard; Burns, Kevin D

    2016-07-19

    Vascular damage contributes to the high cardiovascular morbidity and mortality in end-stage renal disease (ESRD). Increased aortic stiffness measured by carotid-femoral pulse wave velocity (cf-PWV) is a strong and independent predictor of the cardiovascular risk in ESRD patients. Recently, there has been considerable interest in developing strategies to lessen the progression of arterial stiffness in ESRD patients using cf-PWV as a tool to monitor therapeutic responses, but their benefit on the long-term cardiovascular risk is not known. Appraisal of the effects of existing stiffness-based interventions on the cf-PWV would facilitate selecting optimal therapies to be tested in randomized clinical trials. The aim of this systematic review will be to evaluate the impact of arterial stiffness-based interventions on the cf-PWV in ESRD patients. Secondarily, for each intervention, we will determine the minimal duration needed to achieve a significant reduction of cf-PWV, the minimal cf-PWV reduction threshold or effect size, and adverse events. This review will be conducted using MEDLINE, EMBASE, and EBM Reviews. We will select clinical trials and observational studies (cohort, case-control, and before/after studies and case series) that evaluated pharmacologic or non-pharmacologic interventions in which the primary effect is to improve structural and/or dynamic components of arterial stiffness in adults with stage 5 chronic kidney disease. The primary outcome of interest will be cf-PWV. Study selection and data collection will be performed by two reviewers. Validated tools will be used to assess the methodological quality and risk of bias among different study designs. We will describe all included citations according to study characteristics, methodological quality, and outcomes. Suitability for meta-analysis will be determined by the degree of clinical and statistical heterogeneity between studies. If appropriate, we will calculate effect estimates by obtaining the

  10. More than just a urinary catheter — Haemorrhage control by using a Foley catheter in a penetrating aortic root injury

    Directory of Open Access Journals (Sweden)

    Adel Elmoghrabi

    2016-08-01

    Full Text Available The prevalence of great vessel injuries in thoracic trauma is reported at 0.3–10%, predominantly due to a penetrating mechanism. Thoracic aortic injuries, more specifically those within proximity of the aortic root are challenging to manage and unceasing bleeding hampers adequate visualisation for performing repair. We report a case of a 31-year-old male that presented to the emergency department 1 h after sustaining a stab wound injury within proximity of the left upper sternal border. Vital signs were stable on presentation. Physical examination revealed a 1.5 cm laceration in the 3rd intercostal space. Chest X-ray revealed a small left pneumothorax, FAST scan was negative, and CT of the chest revealed left sided haemopneumothorax and haemopericardium. The patient was emergently transferred to the operating room where median thoracotomy was performed. A significant amount of bleeding was observed originating from a 1 cm laceration of the aortic root. Bleeding was controlled using a Foley catheter after unsuccessful attempts of digital compression, and the laceration was repaired using pledgeted sutures. Postoperative echocardiography and CT scan of the chest revealed normal cardiac functions with resolution of haemopericardium and haemopneumothorax, and the patient was discharged in a stable condition. High index of suspicion should be maintained for injury to the great vessels in patients with penetrating chest injuries, despite apparent haemodynamic stability. In this case, balloon tamponade using a Foley catheter served as a quick and simple technique that resulted in an almost bloodless field, facilitating adequate visualisation for definitive repair. Although the use of this technique has been previously described, this report serves as a reminder that a Foley catheter can be successfully used for balloon catheter tamponade in injuries to the aortic root. Keywords: Aortic root, Injury, Foley's catheter, Balloon catheter, Aorta

  11. Retrograde ascending aortic dissection during or after thoracic aortic stent graft placement: insight from the European registry on endovascular aortic repair complications

    DEFF Research Database (Denmark)

    Eggebrecht, Holger; Thompson, Matt; Rousseau, Hervé

    2009-01-01

    BACKGROUND: Single-center reports have identified retrograde ascending aortic dissection (rAAD) as a potentially lethal complication of thoracic endovascular aortic repair (TEVAR). METHODS AND RESULTS: Between 1995 and 2008, 28 centers participating in the European Registry on Endovascular Aortic...

  12. Long-Term Risk for Aortic Complications After Aortic Valve Replacement in Patients With Bicuspid Aortic Valve Versus Marfan Syndrome.

    Science.gov (United States)

    Itagaki, Shinobu; Chikwe, Joanna P; Chiang, Yuting P; Egorova, Natalia N; Adams, David H

    2015-06-09

    Bicuspid aortic valves are associated with valve dysfunction, ascending aortic aneurysm and dissection. Management of the ascending aorta at the time of aortic valve replacement (AVR) in these patients is controversial and has been extrapolated from experience with Marfan syndrome, despite the absence of comparative long-term outcome data. This study sought to assess whether the natural history of thoracic aortopathy after AVR in patients with bicuspid aortic valve disease is substantially different from that seen in patients with Marfan syndrome. In this retrospective comparison, outcomes of 13,205 adults (2,079 with bicuspid aortic valves, 73 with Marfan syndrome, and 11,053 control patients with acquired aortic valve disease) who underwent primary AVR without replacement of the ascending aorta in New York State between 1995 and 2010 were compared. The median follow-up time was 6.6 years. The long-term incidence of thoracic aortic dissection was significantly higher in patients with Marfan syndrome (5.5 ± 2.7%) compared with those with bicuspid valves (0.55 ± 0.21%) and control group patients (0.41 ± 0.08%, p Marfan syndrome (10.8 ± 4.4%) compared with those with bicuspid valves (4.8 ± 0.8%) and control group patients (1.4 ± 0.2%) (p Marfan syndrome were significantly more likely to undergo thoracic aortic surgery in late follow-up (10.4 ± 4.3%) compared with those with bicuspid valves (2.5 ± 0.6%) and control group patients (0.50 ± 0.09%) (p Marfan syndrome compared with those with bicuspid aortic valves confirm that operative management of patients with bicuspid aortic valves should not be extrapolated from Marfan syndrome and support discrete treatment algorithms for these different clinical entities. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  13. Aortic Dissection Type A in Alpine Skiers

    Directory of Open Access Journals (Sweden)

    Thomas Schachner

    2013-01-01

    Full Text Available Patients and Methods. 140 patients with aortic dissection type A were admitted for cardiac surgery. Seventy-seven patients experienced their dissection in the winter season (from November to April. We analyzed cases of ascending aortic dissection associated with alpine skiing. Results. In 17 patients we found skiing-related aortic dissections. Skiers were taller (180 (172–200 cm versus 175 (157–191 cm, and heavier (90 (68–125 kg versus 80 (45–110 kg, than nonskiers. An extension of aortic dissection into the aortic arch, the descending thoracic aorta, and the abdominal aorta was found in 91%, 74%, and 69%, respectively, with no significant difference between skiers and nonskiers. Skiers experienced RCA ostium dissection requiring CABG in 17.6% while this was true for 5% of nonskiers (. Hospital mortality of skiers was 6% versus 13% in nonskiers (. The skiers live at an altitude of 170 (0–853 m.a.s.l. and experience their dissection at 1602 (1185–3105; m.a.s.l. In 82% symptom start was during recreational skiing without any trauma. Conclusion. Skiing associated aortic dissection type A is usually nontraumatic. The persons affected live at low altitudes and practice an outdoor sport at unusual high altitude at cold temperatures. Postoperative outcome is good.

  14. Aortic Dissection Type A in Alpine Skiers

    Science.gov (United States)

    Schachner, Thomas; Fischler, Nikolaus; Dumfarth, Julia; Bonaros, Nikolaos; Krapf, Christoph; Schobersberger, Wolfgang; Grimm, Michael

    2013-01-01

    Patients and Methods. 140 patients with aortic dissection type A were admitted for cardiac surgery. Seventy-seven patients experienced their dissection in the winter season (from November to April). We analyzed cases of ascending aortic dissection associated with alpine skiing. Results. In 17 patients we found skiing-related aortic dissections. Skiers were taller (180 (172–200) cm versus 175 (157–191) cm, P = 0.008) and heavier (90 (68–125) kg versus 80 (45–110) kg, P = 0.002) than nonskiers. An extension of aortic dissection into the aortic arch, the descending thoracic aorta, and the abdominal aorta was found in 91%, 74%, and 69%, respectively, with no significant difference between skiers and nonskiers. Skiers experienced RCA ostium dissection requiring CABG in 17.6% while this was true for 5% of nonskiers (P = 0.086). Hospital mortality of skiers was 6% versus 13% in nonskiers (P = 0.399). The skiers live at an altitude of 170 (0–853) m.a.s.l. and experience their dissection at 1602 (1185–3105; P < 0.001) m.a.s.l. In 82% symptom start was during recreational skiing without any trauma. Conclusion. Skiing associated aortic dissection type A is usually nontraumatic. The persons affected live at low altitudes and practice an outdoor sport at unusual high altitude at cold temperatures. Postoperative outcome is good. PMID:23971024

  15. Quantification of abdominal aortic deformation after EVAR

    Science.gov (United States)

    Demirci, Stefanie; Manstad-Hulaas, Frode; Navab, Nassir

    2009-02-01

    Quantification of abdominal aortic deformation is an important requirement for the evaluation of endovascular stenting procedures and the further refinement of stent graft design. During endovascular aortic repair (EVAR) treatment, the aortic shape is subject to severe deformation that is imposed by medical instruments such as guide wires, catheters, and, the stent graft. This deformation can affect the flow characteristics and morphology of the aorta which have been shown to be elicitors for stent graft failures and be reason for reappearance of aneurysms. We present a method for quantifying the deformation of an aneurysmatic aorta imposed by an inserted stent graft device. The outline of the procedure includes initial rigid alignment of the two abdominal scans, segmentation of abdominal vessel trees, and automatic reduction of their centerline structures to one specified region of interest around the aorta. This is accomplished by preprocessing and remodeling of the pre- and postoperative aortic shapes before performing a non-rigid registration. We further narrow the resulting displacement fields to only include local non-rigid deformation and therefore, eliminate all remaining global rigid transformations. Finally, deformations for specified locations can be calculated from the resulting displacement fields. In order to evaluate our method, experiments for the extraction of aortic deformation fields are conducted on 15 patient datasets from endovascular aortic repair (EVAR) treatment. A visual assessment of the registration results and evaluation of the usage of deformation quantification were performed by two vascular surgeons and one interventional radiologist who are all experts in EVAR procedures.

  16. The link between exercise and titin passive stiffness.

    Science.gov (United States)

    Lalande, Sophie; Mueller, Patrick J; Chung, Charles S

    2017-09-01

    What is the topic of this review? This review focuses on how in vivo and molecular measurements of cardiac passive stiffness can predict exercise tolerance and how exercise training can reduce cardiac passive stiffness. What advances does it highlight? This review highlights advances in understanding the relationship between molecular (titin-based) and in vivo (left ventricular) passive stiffness, how passive stiffness modifies exercise tolerance, and how exercise training may be therapeutic for cardiac diseases with increased passive stiffness. Exercise can help alleviate the negative effects of cardiovascular disease and cardiovascular co-morbidities associated with sedentary behaviour; this may be especially true in diseases that are associated with increased left ventricular passive stiffness. In this review, we discuss the inverse relationship between exercise tolerance and cardiac passive stiffness. Passive stiffness is the physical property of cardiac muscle to produce a resistive force when stretched, which, in vivo, is measured using the left ventricular end diastolic pressure-volume relationship or is estimated using echocardiography. The giant elastic protein titin is the major contributor to passive stiffness at physiological muscle (sarcomere) lengths. Passive stiffness can be modified by altering titin isoform size or by post-translational modifications. In both human and animal models, increased left ventricular passive stiffness is associated with reduced exercise tolerance due to impaired diastolic filling, suggesting that increased passive stiffness predicts reduced exercise tolerance. At the same time, exercise training itself may induce both short- and long-term changes in titin-based passive stiffness, suggesting that exercise may be a treatment for diseases associated with increased passive stiffness. Direct modification of passive stiffness to improve exercise tolerance is a potential therapeutic approach. Titin passive stiffness itself may

  17. Constitutive Modelling of Resins in the Stiffness Domain

    Science.gov (United States)

    Klasztorny, M.

    2004-09-01

    An analytic method for inverting the constitutive compliance equations of viscoelasticity for resins is developed. These equations describe the HWKK/H rheological model, which makes it possible to simulate, with a good accuracy, short-, medium- and long-term viscoelastic processes in epoxy and polyester resins. These processes are of first-rank reversible isothermal type. The time histories of deviatoric stresses are simulated with three independent strain history functions of fractional and normal exponential types. The stiffness equations are described by two elastic and six viscoelastic constants having a clear physic meaning (three long-term relaxation coefficients and three relaxation times). The time histories of axiatoric stresses are simulated as perfectly elastic. The inversion method utilizes approximate constitutive stiffness equations of viscoelasticity for the HWKK/H model. The constitutive compliance equations for the model are a basis for determining the exact complex shear stiffness, whereas the approximate constitutive stiffness equations are used for determining the approximate complex shear stiffness. The viscoelastic constants in the stiffness domain are derived by equating the exact and approximate complex shear stiffnesses. The viscoelastic constants are obtained for Epidian 53 epoxy and Polimal 109 polyester resins. The accuracy of the approximate constitutive stiffness equations are assessed by comparing the approximate and exact complex shear stiffnesses. The constitutive stiffness equations for the HWKK/H model are presented in uncoupled (shear/bulk) and coupled forms. Formulae for converting the constants of shear viscoelasticity into the constants of coupled viscoelasticity are given as well.

  18. Aorta measurements are heritable and influenced by bicuspid aortic valve

    Directory of Open Access Journals (Sweden)

    Lisa J Martin

    2011-09-01

    Full Text Available Abstract: Word Count 266, 1609 charactersObjectives: To determine whether the contributions of genetics and bicuspid aortic valve (BAV independently influence aortic (Ao dimensions.Background: Ao dilation is a risk factor for aneurysm, dissection, and sudden cardiac death. Frequent association of BAV with Ao dilation implicates a common underlying defect possibly due to genetic factors. Methods: Families enriched for BAV underwent standardized transthoracic echocardiography. In addition to BAV status, echocardiographic measures of Ao (annulus to descending Ao, pulmonary artery and mitral valve annulus diameters were obtained. Using variance components analysis, heritability was estimated with and without BAV status. Additionally, bivariate genetic analyses between Ao dimensions and BAV were performed.Results: Our cohort was obtained from 209 families enriched for BAV. After adjusting for age, body surface area and sex, individuals with BAV had a statistically significant increase in all echocardiographic measurements (p < 0.006 except descending Ao and mitral valve annulus. Individuals with BAV were at greater odds of having Ao dilation (OR = 4.44, 95% CI 2.93 – 6.72 than family members without BAV. All echocardiographic measurements exhibited moderate to strong heritability (0.25 to 0.53, and these estimates were not influenced by inclusion of BAV as a covariate. Bivariate genetic analyses supported that the genetic correlation between BAV and echo measures were not significantly different from zero.Conclusions: We show for the first time that echocardiographic measurements of Ao, pulmonary artery and mitral valve annulus diameters are quantitative traits that exhibit significant heritability. In addition, our results suggest the presence of BAV independently influences the proximal Ao and pulmonary artery measures but not those in the descending Ao or mitral valve annulus.

  19. Aortic events in a nationwide Marfan syndrome cohort

    DEFF Research Database (Denmark)

    Groth, Kristian A; Krag, Kirstine Stochholm; Hove, Hanne

    2017-01-01

    BACKGROUND: Marfan syndrome is associated with morbidity and mortality due to aortic dilatation and dissection. Preventive aortic root replacement has been the standard treatment in Marfan syndrome patients with aortic dilatation. In this study, we present aortic event data from a nationwide Marfan...... syndrome cohort. METHOD: The nationwide cohort of Danish Marfan syndrome patients was established from the Danish National Patient Registry and the Cause of Death Register, where we retrieved information about aortic surgery and dissections. We associated aortic events with age, sex, and Marfan syndrome...

  20. Ambulatory Arterial Stiffness Indexes in Cushing's Syndrome.

    Science.gov (United States)

    Battocchio, Marialberta; Rebellato, Andrea; Grillo, Andrea; Dassie, Francesca; Maffei, Pietro; Bernardi, Stella; Fabris, Bruno; Carretta, Renzo; Fallo, Francesco

    2017-03-01

    Long-standing exposure to endogenous cortisol excess is associated with high cardiovascular risk. The aim of our study was to investigate arterial stiffness, which has been recognized as an independent predictor of adverse cardiovascular outcome, in a group of patients with Cushing's syndrome. Twenty-four patients with Cushing's syndrome (3 males, mean age 49±13 years; 20 pituitary-dependent Cushing's disease and 4 adrenal adenoma) underwent 24-h ambulatory blood pressure monitoring (ABPM) and evaluation of cardiovascular risk factors. The Ambulatory Arterial Stiffness Index (AASI) and symmetric AASI (sAASI) were derived from ABPM tracings. Cushing patients were divided into 8 normotensive (NOR-CUSH) and 16 hypertensive (HYP-CUSH) patients, and were compared with 8 normotensive (NOR-CTR) and 16 hypertensive (HYP-CTR) control subjects, matched for demographic characteristics, 24-h ABPM and cardiometabolic risk factors. The AASI and sAASI indexes were significantly higher in Cushing patients than in controls, either in the normotensive (p=0.048 for AASI and p=0.013 for sAASI) or in the hypertensive (p=0.004 for AASI and p=0.046 for sAASI) group. No difference in metabolic parameters was observed between NOR-CUSH and NOR-CTR or between HYP-CUSH and HYP-CTR groups. AASI and sAASI were both correlated with urinary cortisol in patients with endogenous hypercortisolism (Spearman's rho=0.40, p=0.05, and 0.61, p=0.003, respectively), while no correlation was found in controls. Both AASI and sAASI are increased in Cushing syndrome, independent of BP elevation, and may represent an additional cardiovascular risk factor in this disease. The role of excess cortisol in arterial stiffness has to be further clarified. © Georg Thieme Verlag KG Stuttgart · New York.

  1. Intestinal lymphangiectasia and reversible high liver stiffness.

    Science.gov (United States)

    Milazzo, Laura; Peri, Anna Maria; Lodi, Lucia; Gubertini, Guido; Ridolfo, Anna Lisa; Antinori, Spinello

    2014-08-01

    Primary intestinal lymphangiectasia (PIL) is a protein-losing enteropathy characterized by tortuous and dilated lymph channels of the small bowel. The main symptoms are bilateral lower limb edema, serosal effusions, and vitamin D malabsorption resulting in osteoporosis. We report here a case of long-lasting misdiagnosed PIL with a peculiar liver picture, characterized by a very high stiffness value at transient elastography, which decreased with clinical improvement. The complex interplay between lymphatic and hepatic circulatory system is discussed. © 2014 by the American Association for the Study of Liver Diseases.

  2. Relative stiffness of flat conductor cables

    Science.gov (United States)

    Hankins, J. D.

    1976-01-01

    The measurement of the bending moment required to obtain a given deflection in short lengths of flat conductor cable (FCC) is presented in this report. Experimental data were taken on 10 different samples of FCC and normalized to express all bending moments (relative stiffness factor) in terms of a cable 5.1 cm (2.0 in.) in width. Data are presented in tabular and graphical form for the covenience of designers who may be interested in finding torques exerted on critical components by short lengths of FCC.

  3. Aortic annulus and ascending aorta: Comparison of preoperative and periooperative measurement in patients with aortic stenosis

    International Nuclear Information System (INIS)

    Smid, Michal; Ferda, Jiri; Baxa, Jan; Cech, Jakub; Hajek, Tomas; Kreuzberg, Boris; Rokyta, Richard

    2010-01-01

    Background: Precise determination of the aortic annulus size constitutes an integral part of the preoperative evaluation prior to aortic valve replacement. It enables the estimation of the size of prosthesis to be implanted. Knowledge of the size of the ascending aorta is required in the preoperative analysis and monitoring of its dilation enables the precise timing of the operation. Our goal was to compare the precision of measurement of the aortic annulus and ascending aorta using magnetic resonance (MR), multidetector-row computed tomography (MDCT), transthoracic echocardiography (TTE), and transoesophageal echocardiography (TEE) in patients with degenerative aortic stenosis. Methods and results: A total of 15 patients scheduled to have aortic valve replacement were enrolled into this prospective study. TTE was performed in all patients and was supplemented with TEE, CT and MR in the majority of patients. The values obtained were compared with perioperative measurements. For the measurement of aortic annulus, MR was found to be the most precise technique, followed by MDCT, TTE, and TEE. For the measurement of ascending aorta, MR again was found to be the most precise technique, followed by MDCT, TEE, and TTE. Conclusion: In our study, magnetic resonance was found to be the most precise technique for the measurement of aortic annulus and ascending aorta in patients with severe degenerative aortic stenosis.

  4. Systematic review of the outcome of aortic valve replacement in patients with aortic stenosis

    NARCIS (Netherlands)

    Sharma, Umesh C.; Barenbrug, Paul; Pokharel, Saraswati; Dassen, Willem R. M.; Pinto, Yigal M.; Maessen, Jos G.

    2004-01-01

    BACKGROUND: After the establishment of aortic valve replacement procedure for aortic stenosis, there are heterogeneous studies and varying reports on outcome. An analysis that compares individual studies to summarize the overall effect is still lacking. This study systematically analyzes the change

  5. Transcatheter aortic valve implantation: emerging role in poor left ventricular function severe aortic stenosis?

    Directory of Open Access Journals (Sweden)

    K. M. John Chan

    2014-01-01

    Full Text Available Transcatheter aortic valve implantation (TAVI has become an established treatment option for high risk elderly patients with symptomatic severe aortic stenosis. Its role in less high risk patients is being evaluated in clinical trials. Patients with severely impaired left ventricular function may be another group who may benefit from this emerging percutaneous treatment option.

  6. Effect of candesartan treatment on left ventricular remodeling after aortic valve replacement for aortic stenosis

    DEFF Research Database (Denmark)

    Dahl, Jordi S; Videbaek, Lars; Poulsen, Mikael K

    2010-01-01

    In hypertension, angiotensin receptor blockers can augment regression of left ventricular (LV) hypertrophy. It is not known whether this also is the case after aortic valve replacement (AVR) for severe aortic stenosis (AS). To test the hypothesis that treatment with candesartan in addition to con...

  7. Development of an In Vitro PIV Setup for Preliminary Investigation of the Effects of Aortic Compliance on Flow Patterns and Hemodynamics.

    Science.gov (United States)

    Büsen, Martin; Arenz, Christian; Neidlin, Michael; Liao, Sam; Schmitz-Rode, Thomas; Steinseifer, Ulrich; Sonntag, Simon J

    2017-09-01

    The aorta with its compliance plays a major role in hemodynamics as it saves a portion of ejected blood during systole which is then released in diastole. The aortic compliance decreases with increasing age, which is related to several cardiovascular imparities and diseases. Changes in flow patterns and pressure curves, due to varying aortic compliance, are difficult to investigate in vivo. As a result, the aim of the present work was to develop an in vitro setup enabling standardized investigations on the effect of compliance changes on flow patterns and pressure curves. Therefore an experimental setup with an anatomically correct silicone phantom of the aortic arch was developed, suitable for optical flow measurements under pulsatile inflow conditions. The setup was developed for precise adjustments of different compliances and optical flow measurements. Particle image velocimetry measurements were carried out downstream of the aortic valve in the center plane perpendicular to the valve with compliance adjusted between 0.62 × 10 -3 to 1.82 × 10 -3  mmHg -1 . Preliminary results of the in vitro investigations showed that decreases in compliance results in significant increases in pressure changes with respect to time (dp/dt) and altered pressure curves in the aortic arch. In terms of flow, an increased aortic stiffness lead to higher mean velocities and decreased vortex development in the aortic sinuses. As in vivo validation and translation remains difficult, the results have to be considered as preliminary in vitro insights into the mechanisms of (age-related) compliance changes.

  8. The outcome after aortic valve-sparing (David) operation in 179 patients: a single-centre experience.

    Science.gov (United States)

    Leontyev, Sergey; Trommer, Constanze; Subramanian, Sreekumar; Lehmann, Sven; Dmitrieva, Yaroslava; Misfeld, Martin; Mohr, Friedrich W; Borger, Michael A

    2012-08-01

    The David aortic valve-sparing reimplantation (AVr-D) operation is increasingly being used in patients with aortic root aneurysmal disease and pliable aortic cusps. The objective of this study was to assess our early and medium-term outcomes with the AVr-D operation. Between 2003 and 2011, a total of 179 patients underwent AVr-D procedures. The mean patient age was 49.7 ± 15.1 years, and 23.5% (n = 42) were females. Marfan syndrome was present in 17.3% of patients (n = 31), and acute Type A aortic dissection in 15.6% (n = 28). Clinical follow-up was 100% complete and was 1.8 ± 1.6 years (0 days to 7.5 years) long. Echocardiographic follow-up was performed 2.2 ± 1.5 years (0 days to 7.5 years) postoperatively and was 77% complete. Early mortality was 1.1% (n = 2), with both deaths occurring in patients with Type A dissection. Pre-discharge echocardiography revealed no patients with >2+ aortic insufficiency (AI), 19.6% of patients (n = 34) with 1+ or 2+ AI and 80.4% of patients (n = 145) with trace or no AI. Left ventricular end-diastolic diameters decreased significantly from 5.6 ± 0.9 to 5.1 ± 0.8 cm early postoperatively (P valve re-replacement during follow-up, two due to early endocarditis and two due to non-coronary leaflet prolapse in Marfan patients. Five-year freedom from aortic valve reoperation was 95.9 ± 2.0%. AVr-D is associated with a low mortality and morbidity rate, even in patients with Type A aortic dissection. Although a slightly higher rate of recurrent AI may be present in patients with Marfan syndrome, freedom from recurrent AI and reoperation remains excellent during medium-term follow-up. The David operation should be considered the gold standard for patients with proximal aortic root pathology (aneurysm or dissection) and pliable aortic cusps.

  9. Application of thoracic endovascular aortic repair (TEVAR) in treating dwarfism with Stanford B aortic dissection

    Science.gov (United States)

    Qiu, Jian; Cai, Wenwu; Shu, Chang; Li, Ming; Xiong, Qinggen; Li, Quanming; Li, Xin

    2018-01-01

    Abstract Rationale: To apply thoracic endovascular aortic repair (TEVAR) to treat dwarfism complicated with Stanford B aortic dissection. Patient concerns: In this report, we presented a 63-year-old male patient of dwarfism complicated with Stanford B aortic dissection successfully treated with TEVAR. Diagnoses: He was diagnosed with dwarfism complicated with Stanford B aortic dissection. Interventions: After conservative treatment, the male patient underwent TEVAR at 1 week after hospitalization. After operation, he presented with numbness and weakness of his bilateral lower extremities, and these symptoms were significantly mitigated after effective treatment. At 1- and 3-week after TEVAR, the aorta status was maintained stable and restored. Outcomes: The patient obtained favorable clinical prognosis and was smoothly discharged. During subsequent follow-up, he remained physically stable. Lessons: TEVAR is probably an option for treating dwarfism complicated with Stanford B aortic dissection, which remains to be validated by subsequent studies with larger sample size. PMID:29703033

  10. Realities of proximity facility siting

    International Nuclear Information System (INIS)

    DeMott, D.L.

    1981-01-01

    Numerous commercial nuclear power plant sites have 2 to 3 reactors located together, and a group of Facilities with capabilities for fuel fabrication, a nuclear reactor, a storage area for spent fuel, and a maintenance area for contaminated equipment and radioactive waste storage are being designed and constructed in the US. The proximity of these facilities to each other provides that the ordinary flow of materials remain within a limited area. Interactions between the various facilities include shared resources such as communication, fire protection, security, medical services, transportation, water, electrical, personnel, emergency planning, transport of hazardous material between facilities, and common safety and radiological requirements between facilities. This paper will explore the advantages and disadvantages of multiple facilities at one site. Problem areas are identified, and recommendations for planning and coordination are discussed

  11. Pipe elbow stiffness coefficients including shear and bend flexibility factors for use in direct stiffness codes

    International Nuclear Information System (INIS)

    Perry, R.F.

    1977-01-01

    Historically, developments of computer codes used for piping analysis were based upon the flexibility method of structural analysis. Because of the specialized techniques employed in this method, the codes handled systems composed of only piping elements. Over the past ten years, the direct stiffness method has gained great popularity because of its systematic solution procedure regardless of the type of structural elements composing the system. A great advantage is realized with a direct stiffness code that combines piping elements along with other structural elements such as beams, plates, and shells, in a single model. One common problem, however, has been the lack of an accurate pipe elbow element that would adequately represent the effects of transverse shear and bend flexibility factors. The purpose of the present paper is to present a systematic derivation of the required 12x12 stiffness matrix and load vectors for a three dimensional pipe elbow element which includes the effects of transverse shear and pipe bend flexibility according to the ASME Boiler and Pressure Vessel Code, Section III. The results are presented analytically and as FORTRAN subroutines to be directly incorporated into existing direct stiffness codes. (Auth.)

  12. Stiffness Evolution in Frozen Sands Subjected to Stress Changes

    KAUST Repository

    Dai, Sheng; Santamarina, Carlos

    2017-01-01

    Sampling affects all soils, including frozen soils and hydrate-bearing sediments. The authors monitor the stiffness evolution of frozen sands subjected to various temperature and stress conditions using an oedometer cell instrumented with P-wave transducers. Experimental results show the stress-dependent stiffness of freshly remolded sands, the dominant stiffening effect of ice, creep after unloading, and the associated exponential decrease in stiffness with time. The characteristic time for stiffness loss during creep is of the order of tens of minutes; therefore it is inevitable that frozen soils experience sampling disturbances attributable to unloading. Slow unloading minimizes stiffness loss; conversely, fast unloading causes a pronounced reduction in stiffness probably attributable to the brittle failure of ice or ice-mineral bonding.

  13. Stiffness Evolution in Frozen Sands Subjected to Stress Changes

    KAUST Repository

    Dai, Sheng

    2017-04-21

    Sampling affects all soils, including frozen soils and hydrate-bearing sediments. The authors monitor the stiffness evolution of frozen sands subjected to various temperature and stress conditions using an oedometer cell instrumented with P-wave transducers. Experimental results show the stress-dependent stiffness of freshly remolded sands, the dominant stiffening effect of ice, creep after unloading, and the associated exponential decrease in stiffness with time. The characteristic time for stiffness loss during creep is of the order of tens of minutes; therefore it is inevitable that frozen soils experience sampling disturbances attributable to unloading. Slow unloading minimizes stiffness loss; conversely, fast unloading causes a pronounced reduction in stiffness probably attributable to the brittle failure of ice or ice-mineral bonding.

  14. Analysis of Dynamic Stiffness of Bridge Cap-Pile System

    Directory of Open Access Journals (Sweden)

    Jinhui Chu

    2018-01-01

    Full Text Available In order to investigate the applicability of dynamic stiffness for bridge cap-pile system, a laboratory test was performed. A numerical model was also built for this type of system. The impact load was applied on the cap top and the dynamic stiffness was analysed. Then, the effect of the effective friction area between pile and soil was also considered. Finally, the dynamic stiffness relationship between the single pile and the cap-pile system was also compared. The results show that the dynamic stiffness is a sensitive index and can well reflect the static characteristics of the pile at the elastic stage. There is a significant positive correlation between the vertical dynamic stiffness index and bearing capacity of the cap-pile system in the similar formation environment. For the cap-pile system with four piles, the dynamic stiffness is about four times as large as the single pile between 10 and 20 Hz.

  15. Elastic metamaterial beam with remotely tunable stiffness

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Wei [University of Michigan–Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240 (China); Yu, Zhengyue [School of Naval Architecture, Ocean & Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Wang, Xiaole [School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Lai, Yun [College of Physics, Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Yellen, Benjamin B., E-mail: yellen@duke.edu [University of Michigan–Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240 (China); Department of Mechanical Engineering and Materials Science, Duke University, P.O. Box 90300, Hudson Hall, Durham, North Carolina 27708 (United States)

    2016-02-07

    We demonstrate a dynamically tunable elastic metamaterial, which employs remote magnetic force to adjust its vibration absorption properties. The 1D metamaterial is constructed from a flat aluminum beam milled with a linear array of cylindrical holes. The beam is backed by a thin elastic membrane, on which thin disk-shaped permanent magnets are mounted. When excited by a shaker, the beam motion is tracked by a Laser Doppler Vibrometer, which conducts point by point scanning of the vibrating element. Elastic waves are unable to propagate through the beam when the driving frequency excites the first elastic bending mode in the unit cell. At these frequencies, the effective mass density of the unit cell becomes negative, which induces an exponentially decaying evanescent wave. Due to the non-linear elastic properties of the membrane, the effective stiffness of the unit cell can be tuned with an external magnetic force from nearby solenoids. Measurements of the linear and cubic static stiffness terms of the membrane are in excellent agreement with experimental measurements of the bandgap shift as a function of the applied force. In this implementation, bandgap shifts by as much as 40% can be achieved with ∼30 mN of applied magnetic force. This structure has potential for extension in 2D and 3D, providing a general approach for building dynamically tunable elastic metamaterials for applications in lensing and guiding elastic waves.

  16. Impact of matrix stiffness on fibroblast function

    Energy Technology Data Exchange (ETDEWEB)

    El-Mohri, Hichem; Wu, Yang; Mohanty, Swetaparna; Ghosh, Gargi, E-mail: gargi@umich.edu

    2017-05-01

    Chronic non-healing wounds, caused by impaired production of growth factors and reduced vascularization, represent a significant burden to patients, health care professionals, and health care system. While several wound dressing biomaterials have been developed, the impact of the mechanical properties of the dressings on the residing cells and consequently on the healing of the wounds is largely overlooked. The primary focus of this study is to explore whether manipulation of the substrate mechanics can regulate the function of fibroblasts, particularly in the context of their angiogenic activity. A photocrosslinkable hydrogel platform with orthogonal control over gel modulus and cell adhesive sites was developed to explore the quantitative relationship between ECM compliance and fibroblast function. Increase in matrix stiffness resulted in enhanced fibroblast proliferation and stress fiber formation. However, the angiogenic activity of fibroblasts was found to be optimum when the cells were seeded on compliant matrices. Thus, the observations suggest that the stiffness of the wound dressing material may play an important role in the progression of wound healing. - Highlights: • Proliferation and stress fiber formation of fibroblasts increase with increasing matrix mechanics. • Cell area correlates with the growth of fibroblasts. • Angiogenic activity of fibroblasts optimum when cells seeded on compliant gels.

  17. Multifunctional Stiff Carbon Foam Derived from Bread.

    Science.gov (United States)

    Yuan, Ye; Ding, Yujie; Wang, Chunhui; Xu, Fan; Lin, Zaishan; Qin, Yuyang; Li, Ying; Yang, Minglong; He, Xiaodong; Peng, Qingyu; Li, Yibin

    2016-07-06

    The creation of stiff yet multifunctional three-dimensional porous carbon architecture at very low cost is still challenging. In this work, lightweight and stiff carbon foam (CF) with adjustable pore structure was prepared by using flour as the basic element via a simple fermentation and carbonization process. The compressive strength of CF exhibits a high value of 3.6 MPa whereas its density is 0.29 g/cm(3) (compressive modulus can be 121 MPa). The electromagnetic interference (EMI) shielding effectiveness measurements (specific EMI shielding effectiveness can be 78.18 dB·cm(3)·g(-1)) indicate that CF can be used as lightweight, effective shielding material. Unlike ordinary foam structure materials, the low thermal conductivity (lowest is 0.06 W/m·K) with high resistance to fire makes CF a good candidate for commercial thermal insulation material. These results demonstrate a promising method to fabricate an economical, robust carbon material for applications in industry as well as topics regarding environmental protection and improvement of energy efficiency.

  18. Elastic metamaterial beam with remotely tunable stiffness

    Science.gov (United States)

    Qian, Wei; Yu, Zhengyue; Wang, Xiaole; Lai, Yun; Yellen, Benjamin B.

    2016-02-01

    We demonstrate a dynamically tunable elastic metamaterial, which employs remote magnetic force to adjust its vibration absorption properties. The 1D metamaterial is constructed from a flat aluminum beam milled with a linear array of cylindrical holes. The beam is backed by a thin elastic membrane, on which thin disk-shaped permanent magnets are mounted. When excited by a shaker, the beam motion is tracked by a Laser Doppler Vibrometer, which conducts point by point scanning of the vibrating element. Elastic waves are unable to propagate through the beam when the driving frequency excites the first elastic bending mode in the unit cell. At these frequencies, the effective mass density of the unit cell becomes negative, which induces an exponentially decaying evanescent wave. Due to the non-linear elastic properties of the membrane, the effective stiffness of the unit cell can be tuned with an external magnetic force from nearby solenoids. Measurements of the linear and cubic static stiffness terms of the membrane are in excellent agreement with experimental measurements of the bandgap shift as a function of the applied force. In this implementation, bandgap shifts by as much as 40% can be achieved with ˜30 mN of applied magnetic force. This structure has potential for extension in 2D and 3D, providing a general approach for building dynamically tunable elastic metamaterials for applications in lensing and guiding elastic waves.

  19. Three-dimensional finite volume modelling of blood flow in simulated angular neck abdominal aortic aneurysm

    Science.gov (United States)

    Algabri, Y. A.; Rookkapan, S.; Chatpun, S.

    2017-09-01

    An abdominal aortic aneurysm (AAA) is considered a deadly cardiovascular disease that defined as a focal dilation of blood artery. The healthy aorta size is between 15 and 24 mm based on gender, bodyweight, and age. When the diameter increased to 30 mm or more, the rupture can occur if it is kept growing or untreated. Moreover, the proximal angular neck of aneurysm is categorized as a significant morphological feature with prime harmful effects on endovascular aneurysm repair (EVAR). Flow pattern in pathological vessel can influence the vascular intervention. The aim of this study is to investigate the blood flow behaviours in angular neck abdominal aortic aneurysm with simulated geometry based on patient’s information using computational fluid dynamics (CFD). The 3D angular neck AAA models have been designed by using SolidWorks Software. Consequently, CFD tools are used for simulating these 3D models of angular neck AAA in ANSYS FLUENT Software. Eventually, based on the results, we summarized that the CFD techniques have shown high performance in explaining and investigating the flow patterns for angular neck abdominal aortic aneurysm.

  20. Retroperitoneal aortic hemorrhage caused by penetration of an endovascular stent-graft anchoring barb.

    Science.gov (United States)

    Twine, Christopher P; Winterbottom, Andrew; Shaida, Nadeem; Boyle, Jonathan R

    2013-08-01

    To report a rare case of acute intraoperative retroperitoneal hemorrhage secondary to aortic penetration by the suprarenal anchoring barb on a stent-graft. A 75-year-old patient on dual antiplatelet therapy for coronary stents and low-molecular-weight heparin for atrial thrombus underwent elective endovascular repair of a 6.7-cm infrarenal abdominal aortic aneurysm. A device with suprarenal fixation and metal anchoring barbs was implanted, and a molding balloon was used that at no time covered the proximal bare metal stents or barbs. In recovery, the patient became tachycardic and hypotensive. After resuscitation, imaging identified an anterior barb penetrating the aortic wall, causing the acute retroperitoneal hemorrhage. A decision to treat conservatively rather than resort to open surgery was difficult but ultimately influenced by the patients' high risk for open surgery. The patient was treated by aggressive reversal of heparin and platelet transfusion, and the bleed settled spontaneously. Major surgery and subsequent morbidity may be avoided by medical management of what would appear to be a surgical problem.

  1. Open Treatment of Blunt Injuries of Supra-Aortic Branches: Case Series.

    Science.gov (United States)

    Sladojevic, Milos; Markovic, Miroslav; Ilic, Nikola; Pejkic, Sinisa; Banzic, Igor; Djoric, Predrag; Koncar, Igor; Tomic, Ivan; Davidovic, Lazar

    2016-02-01

    Blunt injuries of the supra-aortic branches are rare entity, and majority of patients die before arrival at the hospital. Those who arrive alive require complex and fast procedure that requires sternotomy. We report 3 successfully managed cases. We report 3 patients with injury of supra-aortic branches. One was treated urgently due to longitudinal rupture on the posterior wall of innominate artery after car accident, and another 2 had chronic false aneurysm located at the very orifice of the right subclavian and left common carotid artery. In first and second patient bypass grafting with a hand-made, Y-shaped, 8-mm Dacron graft from the ascending aorta to the right common carotid and proximal right subclavian artery were performed, whereas in last 1 bypass grafting from the ascending aorta to the cervical part of the left common carotid artery was performed. In our facility, there were no possibilities for any endovascular treatment. When endovascular technology is not available, open surgical repair of blunt injuries of supra-aortic vessels can be performed without complications. No matter to that, endovascular and hybrid procedures should be considered whenever possible. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Direct measurement of the intrinsic ankle stiffness during standing.

    Science.gov (United States)

    Vlutters, M; Boonstra, T A; Schouten, A C; van der Kooij, H

    2015-05-01

    Ankle stiffness contributes to standing balance, counteracting the destabilizing effect of gravity. The ankle stiffness together with the compliance between the foot and the support surface make up the ankle-foot stiffness, which is relevant to quiet standing. The contribution of the intrinsic ankle-foot stiffness to balance, and the ankle-foot stiffness amplitude dependency remain a topic of debate in the literature. We therefore developed an experimental protocol to directly measure the bilateral intrinsic ankle-foot stiffness during standing balance, and determine its amplitude dependency. By applying fast (40 ms) ramp-and-hold support surface rotations (0.005-0.08 rad) during standing, reflexive contributions could be excluded, and the amplitude dependency of the intrinsic ankle-foot stiffness was investigated. Results showed that reflexive activity could not have biased the torque used for estimating the intrinsic stiffness. Furthermore, subjects required less recovery action to restore balance after bilateral rotations in opposite directions compared to rotations in the same direction. The intrinsic ankle-foot stiffness appears insufficient to ensure balance, ranging from 0.93±0.09 to 0.44±0.06 (normalized to critical stiffness 'mgh'). This implies that changes in muscle activation are required to maintain balance. The non-linear stiffness decrease with increasing rotation amplitude supports the previous published research. With the proposed method reflexive effects can be ruled out from the measured torque without any model assumptions, allowing direct estimation of intrinsic stiffness during standing. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Initial clinical experience with a sac-anchoring endoprosthesis for aortic aneurysm repair.

    Science.gov (United States)

    Donayre, Carlos E; Zarins, Christopher K; Krievins, Dainis K; Holden, Andrew; Hill, Andrew; Calderas, Carlos; Velez, Jaime; White, Rodney A

    2011-03-01

    All current aortic endografts depend on proximal and distal fixation to prevent migration. However, migration and rupture can occur, particularly in patients with aortic necks that are short or angulated, or both. We present our initial clinical experience with a new sac-anchoring endoprosthesis designed to anchor and seal the device within the aneurysm sac. The initial worldwide experience using a new endoprosthesis for the treatment of aortic aneurysms (Nellix Endovascular, Palo Alto, Calif) was reviewed. The endoprosthesis consists of dual balloon-expandable endoframes surrounded by polymer-filled endobags designed to obliterate the aneurysm sac and maintain endograft position. Clinical results and follow-up contrast computed tomography (CT) scans at 30 days and 6 and 12 months were reviewed. The endograft was successfully deployed in 21 patients with infrarenal aortic aneurysms measuring 5.7 ± 0.7 cm (range, 4.3-7.4 cm). Two patients with common iliac aneurysms were treated with sac-anchoring extenders that maintained patency of the internal iliac artery. Infusion of 71 ± 37 mL of polymer (range, 19-158 mL) into the aortic endobags resulted in complete aneurysm exclusion in all patients. Mean implant time was 76 ± 35 minutes, with 33 ± 17 minutes of fluoroscopy time and 180 ± 81 mL of contrast; estimated blood loss was 174 ± 116 mL. One patient died during the postoperative period (30-day mortality, 4.8%), and one died at 10 months from non-device-related causes. During a mean follow-up of 8.7 ± 3.1 months and a median of 6.3 months, there were no late aneurysm- or device-related adverse events and no secondary procedures. CT imaging studies at 6 months and 1 year revealed no increase in aneurysm size, no device migration, and no new endoleaks. One patient had a limited proximal type I endoleak at 30 days that resolved at 60 days and remained sealed. One patient has an ongoing distal type I endoleak near the iliac bifurcation, with no change in aneurysm

  4. A novel variable stiffness mechanism for dielectric elastomer actuators

    Science.gov (United States)

    Li, Wen-Bo; Zhang, Wen-Ming; Zou, Hong-Xiang; Peng, Zhi-Ke; Meng, Guang

    2017-08-01

    In this paper, a novel variable stiffness mechanism is proposed for the design of a variable stiffness dielectric elastomer actuator (VSDEA) which combines a flexible strip with a DEA in a dielectric elastomer minimum energy structure. The DEA induces an analog tuning of the transverse curvature of the strip, thus conveniently providing a voltage-controllable flexural rigidity. The VSDEA tends to be a fully flexible and compact structure with the advantages of simplicity and fast response. Both experimental and theoretical investigations are carried out to reveal the variable stiffness performances of the VSDEA. The effect of the clamped location on the bending stiffness of the VSDEA is analyzed, and then effects of the lengths, the loading points and the applied voltages on the bending stiffness are experimentally investigated. An analytical model is developed to verify the availability of this variable stiffness mechanism, and the theoretical results demonstrate that the bending stiffness of the VSDEA decreases as the applied voltage increases, which agree well with the experimental data. Moreover, the experimental results show that the maximum change of the relative stiffness can reach about 88.80%. It can be useful for the design and optimization of active variable stiffness structures and DEAs for soft robots, vibration control, and morphing applications.

  5. Stiffness and the automatic selection of ODE codes

    International Nuclear Information System (INIS)

    Shampine, L.F.

    1984-01-01

    The author describes the basic ideas behind the most popular methods for the numerical solution of ordinary differential equations (ODEs). He takes up the qualitative behavior of solutions of ODEs and its relation ot the propagation of numerical error. Codes for ODEs are intended either for stiff problems or for non-stiff problems. The difference is explained. Users of codes do not have the information needed to recognize stiffness. A code, DEASY, which automatically recognizes stiffness and selects a suitable method is described

  6. Fatigue crack paths under the influence of changes in stiffness

    Directory of Open Access Journals (Sweden)

    G. Kullmer

    2016-02-01

    Full Text Available An important topic of the Collaborative Research Centre TRR 30 of the Deutsche Forschungsgemeinschaft (DFG is the crack growth behaviour in graded materials. In addition, the growth of cracks in the neighbourhood of regions and through regions with different material properties belongs under this topic. Due to the different material properties, regions with differing stiffness compared to the base material may arise. Regions with differing stiffness also arise from ribs, grooves or boreholes. Since secure findings on the propagation behaviour of fatigue cracks are essential for the evaluation of the safety of components and structures, the growth of cracks near changes in stiffness has to be considered, too. Depending on the way a crack penetrates the zone of influence of such a change in stiffness and depending on whether this region is more compliant or stiffer than the surrounding area the crack may grow towards or away from this region. Both cases result in curved crack paths that cannot be explained only by the global loading situation. To evaluate the influence of regions with differing stiffness on the path of fatigue cracks the paths and the stress intensity factors of cracks growing near and through regions with differing stiffness are numerically determined with the program system ADAPCRACK3D. Therefore, arrangements of changes in stiffness modelled as material inclusions with stiffness properties different from the base material or modelled as ribs and grooves are systematically varied to develop basic conclusions about the crack growth behaviour near and through changes in stiffness.

  7. On prestress stiffness analysis of bolt-plate contact assemblies

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard; Pedersen, Pauli

    2008-01-01

    , but with finite element (FE) and contact analysis, it is possible to find the stiffness of the member. In the case of many connections and for practical applications, it is not suitable to make a full FE analysis. The purpose of the present paper is to find simplified expressions for the stiffness of the member......, including the case when the width of the member is limited. The calculation of the stiffness is based on the FE, including the solution to the contact problem, and we express the stiffness as a function of the elastic energy in the structure, whereby the definition of the displacements related...

  8. Ball Bearing Stiffnesses- A New Approach Offering Analytical Expressions

    Science.gov (United States)

    Guay, Pascal; Frikha, Ahmed

    2015-09-01

    Space mechanisms use preloaded ball bearings in order to withstand the severe vibrations during launch.The launch strength requires the calculation of the bearing stiffness, but this calculation is complex. Nowadays, there is no analytical expression that gives the stiffness of a bearing. Stiffness is computed using an iterative algorithm such as Newton-Raphson, to solve the nonlinear system of equations.This paper aims at offering a simplified analytical approach, based on the assumption that the contact angle is constant. This approach gives analytical formulas of the stiffness of preloaded ball bearing.

  9. Low frequency noise reduction using stiff light composite panels

    Institute of Scientific and Technical Information of China (English)

    DENG Yongchang; LIN Weizheng

    2003-01-01

    The experiment presented in this paper is to investigate and analyze the noise reduction at low frequency using stiff light composite panels. Since these composite panels are made of lightweight and stiff materials, this actuation strategy will enable the creation of composite panels for duct noise control without using traditional heavy structural mass. The results suggest that the mass-spring resonance absorption in the case of a comparatively stiff thick panel with a thin flexible plate is more efficient with minimum weight, when subjected to low-frequency (<500 Hz). The efficiency of the panel absorber depends on the mass of the thin flexible plate and the stiffness of the panel.

  10. Automated Normalized Cut Segmentation of Aortic Root in CT Angiography

    NARCIS (Netherlands)

    Elattar, Mustafa; Wiegerinck, Esther; Planken, Nils; VanBavel, Ed; van Assen, Hans; Baan, Jan Jr; Marquering, Henk

    2014-01-01

    Transcatheter Aortic Valve Implantation (TAVI) is a new minimal-invasive intervention for implanting prosthetic valves in patients with aortic stenosis. This procedure is associated with adverse effects like paravalvular leakage, stroke, and coronary obstruction. Accurate automated sizing for

  11. comparative proximate composition and antioxidant vitamins

    African Journals Online (AJOL)

    DR. AMINU

    Keywords: Comparative, proximate composition, antioxidant vitamins, honey. INTRODUCTION ... solution of inverted sugars and complex mixture of other saccharides ... enzymatic browning in apple slices and grape juice. (Khan, 1985).

  12. Proximate, Mineral and Phytochemical Composition of Dioscorea ...

    African Journals Online (AJOL)

    ADOWIE PERE

    Keywords: Dioscorea dumetorum, proximate composition, mineral analysis, phytochemical screening ... were analyzed using atomic absorption ... determined using a Hack Dr/200 Spectrophotometer. ... Lead Acetate. +. +. + .... cosmetics.

  13. Proximate composition and antinutrient content of pumpkin ...

    African Journals Online (AJOL)

    Proximate composition and antinutrient content of pumpkin ( Cucurbita pepo ) and sorghum ( Sorghum bicolor ) flour blends fermented with Lactobacillus plantarum , Aspergillus niger and Bacillus subtilis.

  14. Quantification of aortic regurgitation by magnetic resonance velocity mapping

    DEFF Research Database (Denmark)

    Søndergaard, Lise; Lindvig, K; Hildebrandt, P

    1993-01-01

    The use of magnetic resonance (MR) velocity mapping in the quantification of aortic valvular blood flow was examined in 10 patients with angiographically verified aortic regurgitation. MR velocity mapping succeeded in identifying and quantifying the regurgitation in all patients, and the regurgit......The use of magnetic resonance (MR) velocity mapping in the quantification of aortic valvular blood flow was examined in 10 patients with angiographically verified aortic regurgitation. MR velocity mapping succeeded in identifying and quantifying the regurgitation in all patients...

  15. Hybrid treatment of aortic arch disease

    Science.gov (United States)

    Metzger, Patrick Bastos; Rossi, Fabio Henrique; Moreira, Samuel Martins; Issa, Mario; Izukawa, Nilo Mitsuru; Dinkhuysen, Jarbas J.; Spina Neto, Domingos; Kambara, Antônio Massamitsu

    2014-01-01

    Introduction The management of thoracic aortic disease involving the ascending aorta, aortic arch and descending thoracic aorta are technically challenging and is an area in constant development and innovation. Objective To analyze early and midterm results of hybrid treatment of arch aortic disease. Methods Retrospective study of procedures performed from January 2010 to December 2012. The end points were the technical success, therapeutic success, morbidity and mortality, neurologic outcomes, the rate of endoleaks and reinterventions. Results A total of 95 patients treated for thoracic aortic diseases in this period, 18 underwent hybrid treatment and entered in this study. The average ages were 62.3 years. The male was present in 66.7%. The technical and therapeutic success was 94.5% e 83.3%. The perioperative mortality rate of 11.1%. There is any death during one-year follow- up. The reoperation rates were 16.6% due 2 cases of endoleak Ia and one case of endoleak II. There is any occlusion of anatomic or extra anatomic bypass during follow up. Conclusion In our study, the hybrid treatment of aortic arch disease proved to be a feasible alternative of conventional surgery. The therapeutic success rates and re- interventions obtained demonstrate the necessity of thorough clinical follow-up of these patients in a long time. PMID:25714205

  16. Controlling Bleeding from Proximal and Coronary Ostial Anastomoses by Using Blood Cardioplegia Delivering Antegradely while Performing Bentall Procedure

    Directory of Open Access Journals (Sweden)

    Erol Şener

    2011-04-01

    Full Text Available Bentall procedure is one of the valved conduit techniques which is used in the treatment of aortic valve diseases accompanied by ascending aortic aneurysm and dissection and it is used commonly around the world. In Bentall procedure, which is a complicated and long surgery, the rate of mortality and morbidity are not only related to the operation itself but also to the complications like major neurological events, myocardial damage and bleeding which take place during the intraoperative and postoperative period. Although the quantity and frequency of bleeding is declined with teflon strips and biological tissue glues, modifications of Bentall procedure are still an important problem. This study was conducted retrospectively with 48 patients in terms of early results of complication of bleeding caused specifically by proximal suture line and coronary ostium anastomosis lines controlled by the method of blood cardioplegia while performing Bentall procedure and supracoronary aort replacement in our clinic.

  17. The Efficacy of the Coaxial Technique Using a 6-Fr Introducer Sheath in Stent Placement for Treating the Obstructions Proximal to the Descending Colon

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Il Soo; Park, Sang Woo; Hwang, Dae Yong; Seong, Moo Kyung; Joh, Hee Kyung; Yoon, So Young; Cho, Yo Han; Choe, Won Hyeok [Konkuk University Hospital, Seoul (Korea, Republic of)

    2011-02-15

    We wanted to evaluate the efficacy of stent placement using the coaxial technique with a stiff, long introducer sheath in patients with technical failure using an angiographic catheter for the obstructions proximal to the descending colon. Self-expandable metallic stent placement was attempted under fluoroscopy-guidance in 77 consecutive patients who had malignant colorectal obstruction. Stent placement was performed using an angiographic catheter and a guide wire. If the angiographic catheter could not be advanced over the guide wire into the obstructive lesions proximal to the descending colon, then a 6-Fr introducer sheath was used. The technical success rate, the clinical success rate and the complications were analyzed. Successful stent placement was achieved in 75 of 77 patients (97%). The angiographic catheter failed to advance into the obstructive lesions of 11 patients (M:F = 7:4: mean age, 65.5 years) whose lesions were at the level of the splenic flexure or transverse colon. Therefore, the coaxial technique was implemented in all these 11 patients using a 6-Fr stiff introducer sheath and then the stent placement was successful. There were no complications related to the use of a stiff introducer sheath. Clinical success, which was defined as relief of clinical obstructive bowel symptoms, was obtained within 24 hours in all of patients. The coaxial technique using a stiff introducer sheath can increase the technical success of fluoroscopy-guided, self-expandable metallic stent placement in patients with colonic obstruction proximal to the descending colon

  18. The Efficacy of the Coaxial Technique Using a 6-Fr Introducer Sheath in Stent Placement for Treating the Obstructions Proximal to the Descending Colon

    International Nuclear Information System (INIS)

    Chang, Il Soo; Park, Sang Woo; Hwang, Dae Yong; Seong, Moo Kyung; Joh, Hee Kyung; Yoon, So Young; Cho, Yo Han; Choe, Won Hyeok

    2011-01-01

    We wanted to evaluate the efficacy of stent placement using the coaxial technique with a stiff, long introducer sheath in patients with technical failure using an angiographic catheter for the obstructions proximal to the descending colon. Self-expandable metallic stent placement was attempted under fluoroscopy-guidance in 77 consecutive patients who had malignant colorectal obstruction. Stent placement was performed using an angiographic catheter and a guide wire. If the angiographic catheter could not be advanced over the guide wire into the obstructive lesions proximal to the descending colon, then a 6-Fr introducer sheath was used. The technical success rate, the clinical success rate and the complications were analyzed. Successful stent placement was achieved in 75 of 77 patients (97%). The angiographic catheter failed to advance into the obstructive lesions of 11 patients (M:F = 7:4: mean age, 65.5 years) whose lesions were at the level of the splenic flexure or transverse colon. Therefore, the coaxial technique was implemented in all these 11 patients using a 6-Fr stiff introducer sheath and then the stent placement was successful. There were no complications related to the use of a stiff introducer sheath. Clinical success, which was defined as relief of clinical obstructive bowel symptoms, was obtained within 24 hours in all of patients. The coaxial technique using a stiff introducer sheath can increase the technical success of fluoroscopy-guided, self-expandable metallic stent placement in patients with colonic obstruction proximal to the descending colon

  19. Impact of bicuspid aortic valve on complications and death in infective endocarditis of native aortic valves.

    Science.gov (United States)

    Kahveci, Gokhan; Bayrak, Fatih; Pala, Selcuk; Mutlu, Bulent

    2009-01-01

    We retrospectively investigated the impact of bicuspid aortic valve on the prognosis of patients who had definite infective endocarditis of the native aortic valve.Of 51 patients, a bicuspid aortic valve was present in 22 (43%); the other 29 had tricuspid aortic valves. On average, the patients who had bicuspid valves were younger than those who had tricuspid valves. Patients with a tricuspid valve had larger left atrial diameters and were more likely to have severe mitral regurgitation.Periannular complications, which we detected in 19 patients (37%), were much more common in the patients who had a bicuspid valve (64% vs 17%, P = 0.001). The presence of a bicuspid valve was the only significant independent predictor of periannular complications. The in-hospital mortality rate in the bicuspid group was lower than that in the tricuspid group; however, this figure did not reach statistical significance (9% vs 24%, P = 0.15). In multivariate analysis, left atrial diameter was the only independent predictor associated with an increased risk of death (hazard ratio, 2.19; 95% confidence interval, 1.1-4.5; P = 0.031).In our study, patients with infective endocarditis in a bicuspid aortic valve were younger and had a higher incidence of periannular complications. Although a worse prognosis has been reported previously, we found that infective endocarditis in a native bicuspid aortic valve is not likely to increase the risk of death in comparison with infective endocarditis in native tricuspid aortic valves.

  20. Total Endovascular Aortic Repair in a Patient with Marfan Syndrome.

    Science.gov (United States)

    Amako, Mau; Spear, Rafaëlle; Clough, Rachel E; Hertault, Adrien; Azzaoui, Richard; Martin-Gonzalez, Teresa; Sobocinski, Jonathan; Haulon, Stéphan

    2017-02-01

    The aim of this study is to describe a total endovascular aortic repair with branched and fenestrated endografts in a young patient with Marfan syndrome and a chronic aortic dissection. Open surgery is the gold standard to treat aortic dissections in patients with aortic disease and Marfan syndrome. In 2000, a 38-year-old man with Marfan syndrome underwent open ascending aorta repair for an acute type A aortic dissection. One year later, a redo sternotomy was performed for aortic valve replacement. In 2013, the patient presented with endocarditis and pulmonary infection, which necessitated tracheostomy and temporary dialysis. In 2014, the first stage of the endovascular repair was performed using an inner branched endograft to exclude a 77-mm distal arch and descending thoracic aortic aneurysm. In 2015, a 63-mm thoracoabdominal aortic aneurysm was excluded by implantation of a 4-fenestrated endograft. Follow-up after both endovascular repairs was uneventful. Total aortic endovascular repair was successfully performed to treat a patient with arch and thoraco-abdominal aortic aneurysm associated with chronic aortic dissection and Marfan syndrome. The postoperative images confirmed patency of the endograft and its branches, and complete exclusion of the aortic false lumen. Endovascular repair is a treatment option in patients with connective tissue disease who are not candidates for open surgery. Long-term follow-up is required to confirm these favorable early outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Aortic valve replacement and the stentless Freedom SOLO valve

    NARCIS (Netherlands)

    Wollersheim, L.W.L.M.

    2016-01-01

    Aortic valve stenosis has become the most prevalent valvular heart disease in Europe and North America, and is generally caused by age-related calcification of the aortic valve. For most patients, severe symptomatic aortic stenosis needs effective mechanical relief in the form of valve replacement

  2. Intermittent, Non Cyclic Severe Mechanical Aortic Valve Regurgitation

    Science.gov (United States)

    Choi, Jong Hyun; Song, Seunghwan; Lee, Myung-Yong

    2013-01-01

    Mechanical aortic prosthesis dysfunction can result from thrombosis or pannus formation. We describe an unusual case of intermittent, non cyclic mechanical aortic prosthesis dysfunction due to pannus formation with thrombus in the absence of systolic restriction of disk excursion, that presented with intermittent severe aortic regurgitation. PMID:24459568

  3. Aortic microcalcification is associated with elastin fragmentation in Marfan syndrome

    NARCIS (Netherlands)

    Wanga, Shaynah; Hibender, Stijntje; Ridwan, Yanto; van Roomen, Cindy; Vos, Mariska; van der Made, Ingeborg; van Vliet, Nicole; Franken, Romy; van Riel, Luigi Amjg; Groenink, Maarten; Zwinderman, Aeilko H.; Mulder, Barbara Jm; de Vries, Carlie Jm; Essers, Jeroen; de Waard, Vivian

    2017-01-01

    Marfan syndrome (MFS) is a connective tissue disorder in which aortic rupture is the major cause of death. MFS patients with an aortic diameter below the advised limit for prophylactic surgery ( <5 cm) may unexpectedly experience an aortic dissection or rupture, despite yearly monitoring. Hence,

  4. Challenging Friesian horse diseases : aortic rupture and megaesophagus

    NARCIS (Netherlands)

    Ploeg, M.

    2015-01-01

    Aortic rupture is quite rare in Warmblood horses and is best known as an acute and fatal rupture of the aortic root in older breeding stallions. It has now become clear that aortic rupture, which is diagnosed around an age of 4 years, is more frequent in the Friesian breed than in others. The high

  5. A comparative biomechanical analysis of implants for the stabilization of proximal humerus fractures.

    Science.gov (United States)

    Füchtmeier, B; May, R; Fierlbeck, J; Hammer, J; Nerlich, M

    2006-01-01

    A new humerus nail (Sirus) has become available for the treatment of fractures of the proximal humerus. The aim of the study was the biomechanical comparison of this implant with established systems. 12 matched pairs of human humeri were employed for testing. Three randomized groups were formed (n = 4 pairs). A bending moment of 7.5 Nm and a torsional moment of 8.3 Nm were applied in a test of five loading cycles to all intact bones. Loading was consistently initiated at the distal epiphysis. The consequent deformation at the distal epiphysis was continuously recorded. Then an osteotomy with a defect of 5 mm was created to simulate an unstable subcapital humerus fracture. For paired comparison, one of each pair was stabilized with the Sirus proximal humerus nail. The other side was fixed with a reference implant. The following groups were created.: Group I: Sirus versus Proximal humerus nail (PHN) with spiral blade. Group II: Sirus versus PHILOS plate. Group III: Sirus versus 4.5 mm AO T-plate. The proximal humerus nail (Sirus) demonstrated significantly higher stiffness values than the reference implants for both bending and torsional load. The following values were recorded at a bending moment of 7.5 Nm: Sirus 14.2 mm, PHN 20.7 mm, PHILOS plate 28.1 mm, 4.5 AO T-plate 29.3 mm p model presented here. Supplementary, the Sirus Nail showed higher stiffness values than the PHN. However, the latter are gaining in importance due to the possibility of minimal invasive implantation. Whether this will be associated with functional advantages requires further clinical investigation.

  6. Pulling a polymer with anisotropic stiffness near a sticky wall

    International Nuclear Information System (INIS)

    Tabbara, R; Owczarek, A L

    2012-01-01

    We solve exactly a two-dimensional partially directed walk model of a semi-flexible polymer that has one end tethered to a sticky wall, while a pulling force away from the adsorbing surface acts on the free end of the walk. This model generalizes a number of previously considered adsorption models by incorporating individual horizontal and vertical stiffness effects, in competition with a variable pulling angle. A solution to the corresponding generating function is found by means of the kernel method. While the phases and related phase transitions are similar in nature to those found previously the analysis of the model in terms of its physical variables highlights various novel structures in the shapes of the phase diagrams and related behaviour of the polymer. We review the results of previously considered sub-cases, augmenting these findings to include analysis with respect to the model’s physical variables—namely, temperature, pulling force, pulling angle away from the surface, stiffness strength and the ratio of vertical to horizontal stiffness potentials, with our subsequent analysis for the general model focusing on the effect that stiffness has on this pulling angle range. In analysing the model with stiffness we also pay special attention to the case where only vertical stiffness is included. The physical analysis of this case reveals behaviour more closely resembling that of an upward pulling force acting on a polymer than it does of a model where horizontal stiffness acts. The stiffness–temperature phase diagram exhibits re-entrance for low temperatures, previously only seen for three-dimensional or co-polymer models. For the most general model we delineate the shift in the physical behaviour as we change the ratio of vertical to horizontal stiffness between the horizontal-only and the vertical-only stiffness regimes. We find that a number of distinct physical characteristics will only be observed for a model where the vertical stiffness dominates

  7. Aortic regurgitation after valve-sparing aortic root replacement: modes of failure.

    Science.gov (United States)

    Oka, Takanori; Okita, Yutaka; Matsumori, Masamichi; Okada, Kenji; Minami, Hitoshi; Munakata, Hiroshi; Inoue, Takeshi; Tanaka, Akiko; Sakamoto, Toshihito; Omura, Atsushi; Nomura, Takuo

    2011-11-01

    Despite the positive clinical results of valve-sparing aortic root replacement, little is known about the causes of reoperations and the modes of failure. From October 1999 to June 2010, 101 patients underwent valve-sparing aortic root replacement using the David reimplantation technique. The definition of aortic root repair failure included the following: (1) intraoperative conversion to the Bentall procedure; (2) reoperation performed because of aortic regurgitation; and (3) aortic regurgitation equal to or greater than a moderate degree at the follow-up. Sixteen patients were considered to have repair failure. Three patients required intraoperative conversion to valve replacement, 3 required reoperation within 3 months, and another 8 required reoperation during postoperative follow-up. At initial surgery 5 patients had moderate to severe aortic regurgitation, 6 patients had acute aortic dissections, 3 had Marfan syndrome, 2 had status post Ross operations, 3 had bicuspid aortic valves, and 1 had aortitis. Five patients had undergone cusp repair, including Arantius plication in 3 and plication at the commissure in 2. The causes of early failure in 6 patients included cusp perforation (3), cusp prolapse (3), and severe hemolysis (1). The causes of late failure in 10 patients included cusp prolapse (4), commissure dehiscence (3), torn cusp (2), and cusp retraction (1). Patients had valve replacements at a mean of 23 ± 20.9 months after reimplantation and survived. Causes of early failure after valve-sparing root replacement included technical failure, cusp lesions, and steep learning curve. Late failure was caused by aortic root wall degeneration due to gelatin-resorcin-formalin glue, cusp degeneration, or progression of cusp prolapse. Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  8. Endovascular treatment of false-aneurysm ten years after dacron patch aortoplasty for coarctation of the aortic isthmus. Report of a case.

    Science.gov (United States)

    Illuminati, Giulio; Pacilè, Maria Antonietta; Palumbo, Piergaspare; Salvatori, Filippo Maria; Vietri, Francesco

    2013-01-01

    False aneurysm degeneration is a known complication of patch aortoplasty for coarctation of the aortic isthmus. Open surgical treatment consists of prosthetic graft repair of the involved aorta, often requires circulatory arrest to achieve a safe proximal aortic control and perform proximal anastomosis, and finally is associated with substantial perioperative morbidity. Endografting of the diseased aorta is a valuable alternative to open repair, when feasible, with good short and long term results. We now report one more case of false aneurysm ten years after Dacron patch aortoplasty for isthmic coarctation in a 26-year-old woman, successfully treated by endovascular repair via the left common iliac artery, and a complete exclusion of the aneurysm at two year follow-up.

  9. Synergistic effect of low K and D vitamin status on arterial stiffness in a general population.

    Science.gov (United States)

    Mayer, Otto; Seidlerová, Jitka; Wohlfahrt, Peter; Filipovský, Jan; Cífková, Renata; Černá, Václava; Kučerová, Alena; Pešta, Martin; Fuchsová, Radka; Topolčan, Ondřej; Jardon, Kelly M C; Drummen, Nadja E A; Vermeer, Cees

    2017-08-01

    Both vitamins K and D are nutrients with pleiotropic functions in human tissues. The metabolic role of these vitamins overlaps considerably in calcium homeostasis. We analyzed their potential synergetic effect on arterial stiffness. In a cross-sectional study, we analyzed aortic pulse wave velocity (aPWV) in 1023 subjects from the Czech post-MONICA study. Desphospho-uncarboxylated matrix γ-carboxyglutamate protein (dp-ucMGP), a biomarker of vitamin K status, was measured by sandwich ELISA and 25-hydroxyvitamin D 3 (25-OH-D 3 ) by a commercial immunochemical assay. In a subsample of 431 subjects without chronic disease or pharmacotherapy, we detected rs2228570 polymorphism for the vitamin D receptor. After adjustment for confounders, aPWV was independently associated with both factors: dp-ucMGP [β-coefficient(S.E.M.)=13.91(4.87); P=.004] and 25-OH-D 3 [0.624(0.28); P=.027]. In a further analysis, we divided subjects according to dp-ucMGP and 25-OH-D 3 quartiles, resulting in 16 subgroups. The highest aPWV had subjects in the top quartile of dp-ucMGP plus bottom quartile of 25-OH-D 3 (i.e., in those with insufficient status of both vitamin K and vitamin D), while the lowest aPVW had subjects in the bottom quartile of dp-ucMGP plus top quartile of 25-OH-D 3 [9.8 (SD2.6) versus 6.6 (SD1.6) m/s; PD status, the adjusted odds ratio for aPWV≥9.3 m/s was 6.83 (95% CI:1.95-20.9). The aPWV was also significantly higher among subjects bearing the GG genotype of rs2228570, but only in those with a concomitantly poor vitamin K status. In conclusion, we confirmed substantial interaction of insufficient K and D vitamin status in terms of increased aortic stiffness. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Transverse and Longitudinal proximity effect

    Science.gov (United States)

    Jalan, Pryianka; Chand, Hum; Srianand, Raghunathan

    2018-04-01

    With close pairs (˜1.5arcmin) of quasars (QSOs), absorption in the spectra of a background quasar in the vicinity of a foreground quasar can be used to study the environment of the latter quasar at